This is the unedited transcript for webinar: Best practices for optimizing performance and reducing costs when selecting and using cable and hose carriers. Watch on demand
Mary:
Hello and thank you all for attending today’s webinar Best Practices For Optimizing Performance, Reducing Costs, and Selecting and Using Cable Hose Carriers, brought to you by Design World. We would like to thank our sponsors and presenters, Dynatect Manufacturing Ink.
I’m Mary Gannon, senior editor, and I’ll be your moderator today. Just a couple quick house keeping details before we get started. You will see several boxes on your desktop, all of which can be moved and resized around to suit your preferences. You may open, close or change the layout as you like. The webinar slides, as well as additional resources, can be found in the resource box, initially on the bottom right of your screen. You’ll also see the Q&A box at the lower left. This is where you will enter any questions that you have for after the presentation. Feel free to enter a question throughout the webinar, and they will be answered after our presenters are finished. If we do not get your answer, our presenters will be able to reach out to you afterwards. We also encourage you to tweet with us. Simply sign into the Twitter box. Today’s hashtag is automatically added to your tweets.
If you have any questions, please refer to the help button on the bottom of your screen. Finally, if you are watching this webinar on demand, you can still use all the features I went over, including asking questions. They will be emailed to us and we will forward to the presenters.
Now, please allow me to introduce our speakers today. We have two cable management experts with us. Mark Cunningham is Gortrac Sales Manger at Dynatect Manufacturing, and Mark Zanolla is Gortrac Engineering Manager, also with Dynatect.
Mark Cunningham has more than twenty-five years experience designing, specifying, and selling cable and hose carrier systems. He has visited a wide variety of customer installations throughout North and South America, Europe and Asia, and has participated in many training and educational programs on dynamic cable and hose management.
Mark Zanolla has been in the cable carrier industry for more than twenty-five years as well. He has named three cable carrier patents, and has developed numerous products for the industry.
Now I will hand of the mic to Mark and Mark, and thanks for being here, you guys!
Mark C:
Good morning, thanks Mary, we appreciate the opportunity. We’re going to go over … We’re going to break this down into six areas today, the first one being Basic Carrier Design and Selection, and from there we’ll go onto Selecting Construction, Design Considerations, Optimizing Accessories, Value Added, and Planning for Installation. Again, Mark Zanolla is the engineering manager, I’m the sales manager, together we have traveled all over the world selling and designing cable hose [inaudible 00:02:50], so hopefully we can give you some good information for really optimizing performance and reducing costs.
Cable hose carriers, we recognize the [inaudible 00:03:00] for many people, it’s not as entrancing as a motor or a drive, but properly, they’re very visible, and essentially, hey, broken or mismanaged cable hose carrier is not a good reason for you to lose a customer, so that’s what our goal today is, to give you some good practices.
To begin with, Basic Carrier Design and Selection. To start with, the information that typically you want to get are cable/hose specs, that includes the ODs, the weights, the minimum bending radius; space restrictions; travel orientation; travel length; velocity; acceleration; environment. With this information, what we will do is, first of all, determine the size of the carrier. From there we will determine the length, and finally, the style.
Where we would begin is we’re determining the size. The first thing you do, essentially, is draw a box. All right, this is going to be the cavity of the cable carrier itself. The next thing we’re going to do is add the cable to the hoses that you’d be using. From there, we would determine the “B” dimension. Now, this nomenclature is pretty industry standard, everybody uses “B”, but what we’re talking about is the cavity height. That is not manufacturer dependent. In this case, the cavity height itself of the track is determined by the OD of the largest cable or hose. Now, we generally use a safety factor, again this is industry standard as well. Cables, you want to add ten percent up to the nominal size, and hoses you want to add twenty. The reason you add a little more for hoses are, thee especially high pressure hoses, you get expansions, so you want to give the cables and hoses room to move inside the carrier.
Mark Z.:
Yeah, one other thing I’d put out there, Mark, is especially when we lay the cables, the package out is putting the heavier cable to the outsides and working your way inward with the lighter cables. That helps with balance and stability of the system.
Mark C:
Yeah, that’s a good point Mark raises. What’ll happen is a lot of times, people just send us a list of cables and hoses, and if that’s the case, if we have no idea on how they’re being manifolded or how they’re being laid out, we’re just going to look into the circles. Essentially what we will do, is we will then balance them. There’s some tricks for keeping like sizes with like sizes, putting either the heavy ones in the middle or to either side, so if there’s anything when you’re working with a manufacturer, if you have a specific layout, if there is either a juncture box that these things go in a certain way, it’s a good idea to point that out ahead of time. Because otherwise we’re just going to go ahead and lay them out.
Mark Z.:
Yep.
Mark C:
Yep.
Mark Z.:
No, go ahead, Mark.
Mark C:
The next thing we would do is determine the “A” dimension. This is the cavity width. You determine this by adding the ODs of all the cables and hoses, plus for safety factor, and then the width of any separation that you’re going to use. Typically, separators are a good idea. There’s sometimes they’re not, we’ll get into that later, but what a heavy separator does is essentially keep like cables with like cables. Ideally, you do not want to have a cavity that has more than two times the height of the OD because if you do, they can cross each there. Ideally what you’re going to want to do is make sure that each cavity has no more than twice the height of the largest cable or hose inside it.
In this case, what we’re saying is you’d have a cavity width of at least 2.05 inches, plus the separators. The next thing you do is you’d consult your manufacturer’s catalog for the appropriate series, and then check the “C” and “D” dimensions, again space restrictions, again “C” being the outer width and “D” being the outer height. Obviously you want to make sure that whatever contains your cables and hoses, also fits within whatever envelope you’ve got as well.
This is going to give you essentially the [inaudible 00:07:07] on the series of the carrier that you’re working with. From there, we need to establish the minimum bend radius. One of the advantages of cable carriers is that it will allow you to select a minimum bend radius, that the cable will not bend tighter than. The way you go about doing that is, and it’s tricky … The initial rule of thumb is typical eight to ten times OD because there’s a lot of cables out there. You’re talking about big, five hundred MCM cables, SO cords, these typically are not designed to be high flux. Now, on the other hand, there are some high flux cables, [inaudible 00:07:43] cables, where they’ll go as low as three and a half to five times diameter. Best case, consult the manufacturer. When in doubt, eight to ten times is a rule of thumb, but like any rule of thumb, use it guardedly.
From there, you would consult the catalog to select the closest standard bending radius available, and then you’re going to check the “K” and “H” dimensions against the space restrictions. The “H” is the curve height, so obviously, you’re going to make sure that whatever radius you have, is going to fit inside the envelope that you’ve got, that you have to fit in, making sure that it doesn’t hit anything along the way. The “K” dimensions, or the depot, is when the carrier is fully retracted. Center line pivot point of the first length, to the end of the carrier. This can be a tricky dimension, and not everybody designs for it. I had an application a few years ago, in a pit where the customer had not sized for this, and we made it by less than an eighth of an inch, so you have to be careful because that one will get you in trouble.
From there, you would determine the length. Now, the first thing you need to do is determine, what is the required machine travel? How far are you moving? Then you determine whether the carrier can be center mounted. What this means is, if you mount the stationary end of the track, in the middle of the travel, you will only need half the travel’s worth of cable carrier. What you’ll get is you get an extension, half travel extension, half travel attraction [inaudible 00:09:17] at center point.
You’re going to then consult the catalog for the curvel ength of the selected radius. CL is, again, pretty much industry standard, and the way it is calculated is: pi times radius. This is where you get your curve. Again, another industry standard is to use two safety lengths. Whatever the pitch of the track is, and again pitch is defined by pivot point to center line pivot point on the track, so essentially one length. Virtually, everybody in the industry used two safety lengths. What that means is, if you’ve got a length of five inches, and you are ten inches off center, you can just use travel over two. You want to be careful, though. I was involved in an application many years ago that was eight hundred feet of travel. We asked if they were center mounted, and they said yeah, they are, and it turned out they were pretty close. Over eight hundred feet, they were only six or seven feet off. Unfortunately, because they were seven inch lengths, there was only fourteen inches of safety. Had we not really checked this out, there would have been a disaster. Again, always measure twice cut once.
Again, travel over two, plus offset, plus CL is how you determine the length of cable carrier.
Now, as far as orientations go, there are many different types of orientations. The most common is the Horizontal Lower Flange Fixed. Most of you who have worked with cable carriers, I would guess that you used this type of arrangement. Ideally, you’re going to support this from underneath, at the very least what you want to do is you want to support the mounting bracket, the first few lengths off the end. This will prevent deflection for the end of the carrier hanging in the wind.
Mark Z.:
Yeah, Mark, I think that’s worth really pointing out because that’s one of the most common failure modes, is inadequate support with the lower flange fix, so it’s crucial that that gets supported, and if it’s not able to be supported, fully, then we need to look at it and you need to consult us on that.
Mark C:
There are things we can do to stiffen it, but we need to know about it ahead of time. You want to work with your manufacturer to make sure … A lot of these are on the ground anyway, so it doesn’t matter, but typically if they’re hanging off the machine, having support for at least the mounting bracket and the first two to three, four lengths is going to be critical.
Now, the next application we’re looking at is Horizontal Upper Flange Fixed, or Inverted Application. The lower bracket in this case needs to have support, and this is usually only practical in short travels, because when sag is introduced to this, you begin to have interference. Typically, what’s happening is, unless this is hanging in the wind, if this is on the ground, you need to make sure that you have some kind of sliding or rolling mechanism to go with it, because in the first case, the Horizontal Lower Flange Fixed, what’s happening with is the track is just essentially being picked up and put down. There is no real wear on the track, on the crossbars, on the side frames. In the Horizontal Upper Flange Fix, you’re actually sliding on that surface below, so you need to have something will move with it, or you need, if it’s on the ground, you need to have someone on the bottom of that track, slide blocks or rollers, [inaudible 00:12:42] something just to make sure that you don’t get too much friction.
Moving on from there, Vertical Curve Down. This would probably be the second most common application. Very carrier friendly, what’s happening is, there’s really no wear on the track. It’s simply moving up and down because ideally, what you want to do is you want to [inaudible 00:13:06] the cables and hoses, so they’re riding freely through the neutral access of the carrier. You don’t want to have situations, especially in a long vertical curve down, where the cables and hoses are pooling in the bottom of the track. This is going to cause wear over time, both in your cable and hoses, and it’s also going to put undue strain on the mounting bracket and cause the [inaudible 00:13:25] to wear faster than they normally would.
The next one we’re looking at is Vertical Curve Up. Now, this is common in machine tools, on moving masts up top. There are some tricks to this one, though. First of all, you want to have vertical support, ideally on either side. The longer the travel, the more important this becomes. You see a lot of machine tools do not have this support, although actually, you ideally, again, want to take it off, at least off the mounting bracket, first couple lengths. Also, it becomes critical that [inaudible 00:13:58] or pre-tension’s removed.
In a standard track, what happens is, if you were to take this and lay it down in the floor, you’re going to see that there’s a pre-tension in here, or a positive [inaudible 00:14:09]. The idea is, as most applications are horizontal, you want to have a little bit of extra [inaudible 00:14:16] so that when you load the track up, instead of it beginning to sag, it goes from a positive pre-tension, to flat. While this is beneficial in a horizontal application, in a Vertical Curve Up situation, it will cause the track to lightbulb. Ideally, what you want to do is have the [inaudible 00:14:34] removed, and this is something that the manufacturer needs to do ahead of time, and in combination with that, use the correct support.
Mark, any other suggestions on Vertical Curve Up?
Mark Z.:
No, again, it’s similar to the horizontal, the support is key in these applications, and the inadequate support is really one of the most common failures we see.
Mark C:
Okay. Moving on. Now, in many cases, what’s happening is you’ve got problems with load and weight. We’ll get into some of the issues that occur later on, but a way to either reduce weight or width for that matter, is to break your component, your cable and hose package into two tracks, and have them move in a parallel fashion, they’re moving opposed to each other. This can be done either in a horizontal or in a vertical application. Again, it reduces carrier [inaudible 00:15:32] weight, it reduces the width, but you cannot put a traditional support roller in here, so it does have to have an unsupported stand that will travel naturally.
There are other ways to reduce weight and width, and one of them would be to go to a nested application. This is an alternative to an opposed system. You may want to do this. In some cases, what’ll happen is in order to use an opposed system, you’ve got a single [inaudible 00:16:02] arm, with each carrier coming off the other side, they’re going to move in tandem with each other. In some applications, we’ve seen, you’ll have a situation where you’ve got tracks moving independent of each other, two separate [inaudible 00:16:15] arms but moving in the same path. In a case like that, a nested carrier is one way to go. What you’re essentially doing, is instead of putting them in tandem, you’re putting one inside the other.
Now, this is a little trickier than opposed. The width should be the same for inner and outer. Ideally, you don’t want to have a large variance, however we have done it, and I’ve seen other people do it as well. The “H” dimension, that’s the height of the track, the outer carrier must obviously be larger than the inner, and as a rule of thumb, that difference should be two times the outer length height, should be the difference.
Mark, any other comments on opposed or nested?
Mark Z.:
No, just the clips, like you were mentioning, is important to contain the inner track. We also have to pay attention to the pre-tension of the inner track to make sure, obviously interference is not an issue. It’s pretty straightforward.
Mark C:
Yeah. One thing that’s worth mentioning is that many … There are many cookie cutter applications, horizontal, straight, vertical curve down, these are things that people order over the internet simply through a catalog. Opposed and nested are not necessarily applications that you should just buy through the catalog. Especially nested, you’re going to want to work with a manufacturer. Many offer clips to keep these in place, so that would be one where you’re going to want to consult a manufacturer.
Combination Horizontal and Vertical, this is a situation where you’ve got both horizontal and vertical in the same plane. You’re talking multi-access. Not recommended for long or heavy applications. The reason is that if you look at the upper, when it’s in its vertical mode, as you begin to push horizontally, what’s happening is you’re applying force in a straight trajectory, and what happens is the mass that [inaudible 00:18:14] so you begin to get a bending moment, so there are issues with that. It’s not recommended for longer or heavier applications. The upper bracket may need additional support. Mark, why don’t you take this?
Mark Z.:
Yeah, this is another one where just buying it out of the catalog is tricky and typically we like to design these with the exact travel pattern and make sure that we calculate the length correctly. Like you said, Mark, supporting the upper moving end bracket, again is another … One of the most common issues we see that we have failure there because it’s got that moment [inaudible 00:18:54] causes issues at that point. Consult us on these and make sure we get the right system there.
Mark C:
Okay, and then finally, Side Mounted. That’s where the track is on its side. You might want to do that for space restrictions, or rotary. When it’s on its side, obviously it is not longer being picked up or laid down, so you’re going to need to support that. This can be done with rollers, glide blocks, even a plastic track, right now it’s recommend, [inaudible 00:19:24] blocks. You may want to use something on a plastic track as well, because ideally you don’t want the track to wear. You’d rather have some other kind of medium that can be replaced. Many manufacturers, ourselves included, will offer standard glide blocks, standard rollers, to help in a side-mounted application.
The final, would be a rotational. Now, these are real tricky. This is a multi-access application. We can do a maximum of seven-hundred-twenty degrees of rotation, but we do need to get the information, the inner radius, the outer radius, whether it’s a inner, outer [inaudible 00:19:57] motion, [inaudible 00:19:58] displacement, mounting location … This is something that we heartily recommend that you work with a manufacturer on.
That’s basic carrier design and selection, now we’re going to move on to selection construction. Essentially, when you look at the construction, there’s a lot of things that people ask. “Does the environment require an enclosed carrier?” “What is the required unsupported span?” “What’s the budget?” “Are there high velocities or accelerations?” But really, the most basic question it comes down to, is, “Plastic versus steel?”
We get asked all the time, do we use a plastic track or do we use a steel track? Most manufacturers offer both, there are some that only offer plastic, or only offer steel. Ideally you want to work with the right medium for your application, and the application that you used last week might not necessarily be the same application you use next week, so you may need to move back and forth.
As a general rule, people consider plastic tracks are lighter, less expensive, and easier access. Again, as a general rule, steel carriers are heavier, morel robust, more expensive, and harder access. However, like every generalization, it’s much greater than that. Advances in steel construction, driven by the [inaudible 00:21:19] platform industry and places where weight is a consideration, we’ve seen a lot of development in steel carriers that are lighter and more robust. What happens is you’re looking for something that has a larger, unsupported stand, but in bending applications, you need counterweight, so for every pound you add up front, you need to add, in some cases eight to ten pounds of counterweight in the back, and this is simply money. By coming up with steel tracks that are lighter, have [inaudible 00:21:49] unsupported stands, some of these generalizations are no longer the case.
Another thing to consider is, do you use open versus the closed? Now this one’s pretty simple. There are two considerations. Are there chips present, or debris present, and are these chips red hot? If the answer to either of those questions is no, you do not need that enclosed carrier. Typically they are more expensive, some people like the aesthetics to them, but as a general rule, if you neither have the debris or particulate, you do not need an enclosed carrier. As a matter of fact, finds and dust and things like that can actually get trapped inside. You may be better off with an open track so they can pass through.
If, on the other hand, you do have chips, especially red hots, there are a lot of ways to go. The picture here shows a steel track with aluminum armor plates on the outside. What this does is prevent your red hots from going through. These aluminum arm plates, many manufacturers also offer them with plastic tracks as well, so you can get some of the weight cost advantages of plastic track, but with something that will prevent hot chips from getting in as well.
Here’s some examples of some applications that maybe weren’t quite as straightforward as they appeared at first. The first one here, this is the Hood Canal in Washington State. This is a floating pontoon bridge. This was pretty clearly a plastic track. Mark, what was the travel on this one? It was about three hundred feet?
Mark Z.:
Yeah, it was a little over three hundred foot, and some of the trick here was you had a tray, and it had to be all stainless steel because of just the environment in this area, with the sea water and such, so that was a consideration, as well as the boxed [rank 00:23:37], being the long travel, the box [strength 00:23:39] had to have a robust carrier, so we had bolt in stainless steel bars and we put separation in this one as well, and some different things.
Mark C:
There was also requirements that this had to float. We had to have a self [inaudible 00:23:51] bracket on it as well?
Mark Z.:
Yeah, so on the moving end, we put a plus or minus two inch lateral movement to compensate for the water and the waves and such, and just the general [inaudible 00:24:05], it’s a floating bridge, so … Yeah, that was another special characteristic we had to do there.
Mark C:
Again, this is one that on the surface seemed to be pretty straightforward, plastic cable carrier and [inaudible 00:24:18], but by the time we were done, we made some specialty changes to it, so those bars are actually stainless steel bars. One of the reasons that we needed to do this is that if you look at the picture here, what happens is, as you’re moving back and forth, you do have a bending moment on this track. As you see in this picture right here, with a pretty high grade aluminum bar here, we had failures in the test, so this is why we moved to stainless steel, and this is why it’s very important to consult your manufacturer about anything that is different. In this case, the sea water, you have a lot of travel, and the misalignment.
Another example of what’s pretty clearly a steel track, would be something like this. This one happens to be twenty-four inches. There’s tracks out there where you can actually stand inside the bending [radiuses 00:25:10], inside the length. In a case like that, typically steel construction would be the way to go.
Another example, however, of a steel track, something was basically called out steel, however, one of the issues was, we had to go six-hundred feet per minute. Six-hundred feet per minute on a plastic track would not be considered that fast, however in the case of the steel systems, the lockouts, or [inaudible 00:25:38] what was happening is, we calculated that as the track went back and forth and locked out, you’re going to have some significant problems. Mark, will you just take a sec to explain the concept of this support system, here?
Mark Z.:
Yeah, like Mark said, the speeds typically in steel chain are obviously less than plastic just because of the deformation and the materials, and like you said, in this application, we calculated the stresses to exceed the material limits, so we put a support at the top there, so the chain didn’t see the full impact. It was just, it supported it and almost braked the acceleration and the speed, so we put this support system in there that helped us address that issue with the high speed in the steel chain.
Mark C:
Okay. Finally, here’s actually some more examples. This is an example, this is the Main Street Bridge in Jacksonville, Florida. This is a situation where it looks like a pretty standard plastic track. However, there’s something different about that. That is actually not a standard plastic track. The side bands are standard plastic, but the cross bars are black oxide, steel black oxide. What happened is, because of the winds in the bay, it was calculated that if the track blew out of the guides, that the box strength of a standard plastic track that originally had been spec-ed as, would not work. We did wind calculations, and actually the case here, they did in fact … This track on several occasions, did in fact blow out of the guides, in one case actually hanging up on the metal guide, the track had bent the guide but the track did not break. This is another example of something that looks standard, but it’s important when you look at these, the cookie cutter applications [inaudible 00:27:32], ideally, you want to work with your manufacturer for anything that’s beyond the norm, in this case it paid off.
Finally, here’s an example of something that was pretty standard. It was at Treasure Island Casino in Los Vegas. They had a boat that went around the corner. The original track that was specified here, had a reverse bend in it, it was done because you see this thing curves. What happened is, as this thing filled up, the track was glass-filled nylon, and it was originally a snap-together track here, and it absorbed the water. In conjunction with this reverse bend, the track began to separate after six months. We went in a put in a track here that there’s a standard construction track, with bolted lengths. It’s a modular track, it’s got a solid connection to these lengths. There was no need for a reverse bend radius and even with the water absorption, because it locked, there was no issues. Again, a situation where what seemed to be the standard approach, did not work out to be the correct approach.
Let’s move along to design considerations. Mark, why don’t you take us through some of these?
Mark Z.:
Yeah, so some of the things that play into it, you know with what you mentioned early on, there’s the environment, so there’s some different plating options available. Let me advance that … We’ve got some standard yellow, di-chromate plating which has a certain salt sprayed rating. There is a zinc-nickel plating which increases that significantly two and a half times what a standard yellow di-chromate is, so certain applications where there’s a requirement for salt spray, there are some options available to use.
Then, these are some plastic options in certain applications, like for instance an explosive environment, we use a conductive plastic which has certain surface resistivity. There’s some testing for that, it has to pass to be used in those applications. Polypropylene is another plastic that potentially can be used in high humidity, underwater applications, because it doesn’t absorb moisture. Those are typically good choices for high moisture environment.
Then, we’ve seen, going back again, to the original design, the design information, that you typically don’t want to fill the cavity of the carrier more than say, sixty percent. It’s a general rule, but if you do, this is what can happen, either of these are overstuffed systems here, and you start to show some cable wear, so again, pay attention to the maximum fill, and that rule of thumb, sixty percent fill rate.
Crossbar selection lends itself to cable performance, cable wear performance, so there’s certain bar selections that can be used, that are available. You can see they are the round, in the good category, there’s a round crossbar. It’s aluminum, that’s a good choice. It’s an economical approach. A better approach is to put a sleeve over it, so you get rolling friction versus static friction, which helps reduce that, the cable wear. The best approach is an aluminum flat bar, it provides a wide wear surface, and it also gives you the more robust track, or chain, and then it’s not as cost attractive, but it’s a robust solution.
Mark C:
It’s also more cost effective to have than to replace your cables, down streams. The other thing worth mentioning is that these bars are typically available from most manufacturers in either plastic or steel carriers, so whether you’re using plastic or steel, you can have a variety of different bar options.
Mark Z.:
Yep. Pulling cable off, these are just the kind of general guidelines to installing cable. You don’t want to pull it off a wheel or spiral it off, you want to unreel it like shown there on the right, so that’s just a good practice to installing cables in a chain.
This is an example of a metal chain, with the aluminum flat bar we had discussed, talked about, so a really robust looking option there.
In certain applications, high loading, non-traditional, there’s FBA available that really can help steer us into a good solution. We have steel available to us, plastic, the FBA give us some directional improvements, the getting the right product in, so that plays a good role in a god solution.
There’s certain things that you look for when we launch products, and a good practice is sign offs and quality checks. This is an example of a first article that we had shipped, and again, it’s good practice to have a first article and evaluation.
[inaudible 00:33:34], these are good approaches to … There’s a lot of different mounting brackets and attachments, but [inaudible 00:33:45] and then putting these type of tools in place, or something …Mark C:
Ideally, when you’re selecting your track, it’s important, again, people buy cookie cutter, standard tracks all the time, and the differences are very esoteric. When you’re getting into some complicated applications, equally as important as picking your track, you want to make sure you’re working with a manufacturer who does have good quality systems, who does have good RMV systems and who can support you along the way.
One of the things that we find more and more important is, a lot of companies are adapting lean manufacturing, perform Kaizens, a lot of companies [inaudible 00:34:26] vendors to them. The idea is, planning up front. What are the attributes you’re looking for? Making the cable carrier or selection process work, you want both the product and the process, that you can integrate this with your systems.
As for some of the capabilities to look for, FEA, rapid prototyping, FMEA, APQP, these are just some of the things a lot of manufacturers offer and you want to take advantage of that.
Real quick, actually, I missed a slide. Just an example of over the years, Mark, will you maybe talk a little bit about some of the advanced steel tracks over the years?
Mark Z.:
Yeah, I think Mark, you’d mentioned that before about some evolution in steel chain, and back in 1992, there’s a lot of steel heavy type designs, and over the years, just by the market requirements for lighter weight, more cost attractive solutions, by designing the products to reduce the part counts and reduce the weight by engineering and FEA, and those type of things, all lend itself to I think better products for the market. Lighter weight and strength to weight ratios.
This is another example of a new technology where we call it a screw technology instead of a pin, we actually draw the metal. Again, it eliminates the cost of a pin and also the labor to install it. Also, lighter weight.
Some of the other developments are, this is a hybrid chain where to plastic track, obviously a steel chain has better unsupported span than a plastic chain, so this is using the best of both worlds. We talked a little bit before about speed, and steel chain is limited, or less rated than a plastic, so this takes both into account, where the steel reinforcement band provides the greater unsupported span, where the plastic actually picks up the impact from the speed. The trick is in the design of the metal, in how that rotation is designed. This is a unique design, and it gives a lot of advantage. This shows a prototype of one, actually put together and tested, so that is in development currently.
Like Mark mentioned, APQP, it’s pretty much a best practice for launching products. A lot of motive-based, risk assessment, risk analysis, FMEAs. Some of the things that obviously are good practices, cycle testing and where we’re currently installing a two hundred foot tester that we believe is the biggest in North America, and will allow us to really get some longer travels and better understanding of failure modes. This is an actual picture of the installation. Two hundred foot of travel will give us a lot of capability to understand and develop solutions for our customers. This is the cycle test and collecting data, and what we look for in those applications is sag and end wear, that type of thing.
The capabilities of 3D printing in product development, which is a good thing to have. Once you cut tooling, it’s hard and expensive change. Talked a little bit about the Salzburg Testing and evaluating those different types of platings, so that’s also a good tool and available.
Mark C:
This brings us to one of the … When coming to design considerations, one of the most basic design considerations is the travel. Short travels typically require less up front work. Now, there are exceptions if you have high speeds, but for the most part, it gets trickier with the longer travels. Really, as this says, every cable carrier has an unsupported span, and when you exceed the unsupported span of that track, you need to support it.
Now, there are many ways to support. Typically, in plastic tracks, what happens is sag is considered to be okay in most applications. Some people don’t like the aesthetics of it, but unless you’ve got high velocity, you can generally get away with some sag. When the sag reaches to the point where the upper section lies on the lower section, however, it needs to be supported. Typically, in a plastic track, the way this is done is with lateral support, or a guide trough. What happens here, is center mounted application, the troughs consist of two styles, a deep and a shallow. Different manufacturers do this differently, some have an actual two-stage trough, which is half the trough is actually deep, half the trough is shallow. Other manufacturers will use glide blocks under your side, or rollers, but the principal is that as the track begins to travel further, the track position initially sags and lies on itself, and when the gliding section passes the center point, it transitions to the shallow trough set.
In an opposed system, obviously you would not need a shallow and a deep section, the glide block should just be at a deep trough the whole way. What happens, however, in a guide trough is though, because we talked before about you’re applying force to the straight trajectory, but as this sags, the mass of the carriers before that force plan, you get a bending moment. What we do is, and this is something that most manufacturers do at this point, they’ll actually, instead of using the catalog mounting height, we’ll actually lower the mounting height so that the track begins to glide on itself initially. This is done by introducing some reverse bends, adding a little bit of track to the curve length calculation … This isn’t something you want to do yourself, this is something that you want to consult your manufacturer on, let him know. In most cases, most manufacturers are lowering the mounting heights regardless of velocity. This is something to begin in high velocity applications, but typically, Mark, these days, we typically lower them all the time, correct? Most manufacturers do that as well.
Mark Z.:
Right, and you showed the screenshot of the calculations there, there was obviously total force calculations I take in account, weights and accelerations, and heights and all that. Yeah, generally, we do lower them.
Mark C:
Okay. Now, there are ways to optimize [inaudible 00:41:48] and starting with a guide trough, ideally, what you want to do is you want to make sure that it’s straight. If the guide trough is not installed straight, what’s going to happen is you’re going to get protrusions in the path of track, it’s going to act like a [inaudible 00:41:59], hang up the track.
Now, while we’ve talked about the guide trough being the most common solution, there are disadvantages to a guide trough. First of all, there’s installation, especially if this is up in [inaudible 00:42:11], you’ve got to move the guide trough up there, it’s added expense. The other thing is, even though you know there are ways to reduce friction of the guide trough, it is [inaudible 00:42:20] in itself. Some manufacturers offer rollers or clip-on, modular sliders, but either way you’re still in the guide trough, you still have friction, this can spike even with rollers or a skid plate, because what will happen is if that trough is not perfectly straight, there’s going to be hang-ups and you’re going to see spikes in your [tail 00:42:41] force.
There is technology where you’re actually getting away from that. One is to use support rollers. A single support roller will add three times the maximum unsupported span. Two support rollers, you can actually get four times the unsupported span. Traditionally, support rollers are only used in metal tracks, however more and more we’re using in plastic tracks as well, and some other manufacturers, too.
Another way to do it is with a rolling carriage. This is an example of a track where you’ve got support rollers that actually move throughout the entire system. It moves back and forth so you’re not limited to two support rollers. You don’t have to worry about the radius crashing into them. The problem with rolling carriages, however, they’re expensive, there’s a lot of … It requires a lot of breaking to stop that mass from moving.
There’s new developments out there. This is an example of a track where you’ve got support rollers that actually kick away. As the radius moves into it, it acts as a horizontal support, but as the radius hits it, instead of crashing or breaking, the rollers actually move out of the way, back and forth.
Another way to do it would be to go with either a steel track where you did not … You’ve got a larger unsupported span, or in the case if you had an issue with high speeds or velocities, you could go with a hybrid type of track that offers you a steel skin on the inside to give you unsupported span, but plastic on the outside to prevent it from locking up and allowing you to get away with saving the headache of installation, the cost of either support rollers or a guide trough. That’s just another example of that.
As far as some of the other accessories that you can do, most manufacturers offer clamps. They’re to make sure that the proper amount of cable carrier, problematic cables and hoses are inside the track. Here’s some examples of some separation, some different bars. Mark, want to take a minute to talk about that?
Mark Z.:
Yeah, these are just, like you said, some extender bars and some different bar types that are available, so there’s a lot of things that can be done, just depending on the customer requirements, we have a lot of things available to us.
Mark C:
Okay. Here’s just some other pictures. [Aluminum 00:45:08] rollers. A little bit of aluminum cross bars. This is an example, actually, of a steel track that has been configured to glide upon itself. You’ve got rollers on this. By putting in a reverse bend, you can actually get away with the track gliding on itself. Mark, what would be a reason that you might want to do this?
Mark Z.:
Yeah, so I think it’s just really length of travel, and the weight that this particular system had had, and I think lowering the height and reversing the bend to get it down on itself versus a critical sag condition, and we weren’t able to put support rollers in it because the travel was too long, so it’s one of those longer travels, heavier load type situations that we chose to us this approach.
Mark C:
Okay. Winding up then, one of the other things that’s worth looking at is value added. Everybody wants to work with plug-and-play systems. The trick with value added is to make sure that the value added works for you. At a very basic level, some of the value added service that many manufacturers are capable [inaudible 00:46:15] to offer are pre-installing cables and hoses, and this is something that is a real benefit for some companies, but other customers, because of the changes they do, if you have any non-standard systems, it would never work.
However, there are other things to consider. This is a case where not only are you stuffing the cables and hoses, but actually manifolding, and putting the plug-ins and system [inaudible 00:46:37], you’re getting truly a drop in system. This would be an example of something for the next level, where actually the track is being supplied with not only the [inaudible 00:46:46] box and the manifolds, but actually the entire support systems as well. Here’s an example of a track that’s actually got hangers off of it. This was designed for a medical application, and it had to withstand an 8.0 Richter Scale earthquake. We did the calculations and we figured out that everyone would be dead, but the track would still be hanging there.
As far as another example would be, this was a system that was shipped with everything. Not only do you have the cables, hoses, but you’ve got the manifold structure box and the entire support system was shipped together, so it works both as a shipping method, and then just go ahead and take the whole thing, drop it into the system.
Then, finally, another alternative would be to get the cables and hoses pre-stuffed and sent out on wheels.
Finally, installation, we’ll wrap up with that. We went a little over, we apologize for that, but installation is key. Every track and every installation on paper looks great. It’s worth talking to your manufacturer ahead of time about how you’re going to be using this. If the last step that the manufacturer does it put cross bars on, and the first step that you do is pull those cross bars off to install cables and hoses, it would make more sense to consult ahead of time and have the track sent with the cables and hoses, with the cross bars shipped loosely. What we’ve found is that consulting, especially on a large project or on a new application, spending some time up front, discussing with a manufacturer what’s going to happen, this could save you a lot of time and money down stream.
Little things like, “Is it going up in the air? How do you want the tracks shipped to you? Do you want it in one piece? Do you want it in ten foot assemblies?” There’s a lot of good web conferencing software available now where you can actually have [inaudible 00:48:39] meetings with your manufacturer, and actually do approvals online to speed things up. There’s obviously … Once it gets into the field, that’s where the fun begins, so a good installation comes from planning. Again, measure twice, cut once.
That’s really what we have. We appreciate your interest, and I guess if there’s any questions, we’ll be trying to answer them.
Mary:
Thank you so much, Mark and Mark, and as Mark just said, we are open for questions, so let’s get started here. We’ll start with this first one that came in here. What are the temperature limitations of plastic track?
Mark C:
That’s a good question, and I guess there are many types of plastic. The standard plastic that most people use is glass-filled nylon, so you’re talking nylon six. Mark, what would you say on the high end?
Mark Z.:
Yeah, so two-forty fahrenheit on the high end, but again, per application, we have some availability to increase that with special plastics or additives, but generally it is a minus forty to two-forty fahrenheit, is what we like to see for plastic.
Mark C:
One thing I would say, is one general rule is, a question I’ll see a lot of people ask, “Do I need to have a special for temperature?” What kind of cables are you using? If you’re using standard cables, you’ll typically get away with a standard track. You need to look at that both ways.
I know the coldest application that I’m familiar with is University of Wisconsin is doing a study in Antarctica where they do ice core samples, and that one they’ll operate … They shut down at minus forty. I’ve heard some of the oil fields in [inaudible 00:50:28] get even less than that, but as a practical rule, you’re going to either start to get brittle at about minus forty, correct, so that would be your … Minus forty to two-forty, you say, Mark?
Mark Z.:
Yep.
Mark C:
Okay. That would be our answer.
Mary:
Okay. Thank you. Another one that’s here. What do you consider a high-speed application? What would you rate that at?
Mark C:
Mark, do you want to take that one? More than five feet [crosstalk 00:50:54]
Mark Z.:
Yeah, what’s that?
Mary:
[crosstalk 00:50:59] high-speed applications?
Mark Z.:
Yeah, steel chain is typically rated a hundred-twenty feet a minute. Anything above that for steel chain would be considered a high-velocity application. For plastic chain, anything ten feet per second, in that area, anything north of that starts to … Needs other considerations. I would say [crosstalk 00:51:29]
Mark C:
Usually he’s the conservative one. I would have said five. Wow, that’s …
Mark Z.:
Yeah.
Mark C:
One thing I do want to point out though, is just because … It doesn’t mean it can’t be done, it just means that over those guidelines, you definitely want to start working with the manufacturer. There are things that can be done to make the track perform.
Mark Z.:
Right.
Mary:
Very good. We have time for a couple more questions. If you have any questions, please get them in. In the meantime, we’ll have another one here about separators. We have not used separators in the past, will adding them extend service life?
Mark C:
Maybe. Yes, they can. The trick with separators, as Mark said before, sixty percent is your optimum flow. We recognize that virtually nobody follows these guidelines. I cannot remember the last time I saw track that was only sixty percent stuffed. People typically … We’d love it if the first thing you did was design for cable carrier. We recognize that doesn’t happen down stream. You want to put four pounds of cables inside of a two pound box. That said, separators are effective. What they’ll do is they’ll prevent things from crossing over each other, they can separate media, say air from electric, power from gas. The problem becomes, if you’re over-stuffed, and you add separators to this, it can act like a cheese grater to this. My recommendation would be, often separation is very effective, less than often, separation could sometimes be worse than … Mark, I’m sure you’re going to disagree with me from an engineering standpoint, but what’s your stand there?
Mark Z.:
What was that again, Mark? I didn’t catch it.
Mark C:
What I’m saying is, yeah, maybe, but the thing is, if you’re … On the one hand, if you use cable carriers for a year and you haven’t used separators and it works, why add the expense if it’s working? What it will do, is it will prevent … Go on.
Mark Z.:
Yeah, I think definitely it will extend the service life of the cable and hoses for sure. Crossing over, corkscrewing, that’s one of the typical things we see, over-stuffing and such, but yeah, I think definitely separators are a good thing where we need them.
Mark C:
Okay.
Mary:
Great, thank you! How about another one about lubrication? Should you lubricate steel carriers, and if so, what do you suggest doing and how?
Mark C:
Mark?
Mark Z.:
Yeah, generally, lubrication isn’t required. Should it be required, certain applications have more abrasive environments than we would recommend a dry lubrication, but the majority of applications, lubrication of the steel chain is not required.
Mark C:
One thing we can do, is we can put in, for applications that require real lubricity that you need very low friction on a steel track, first of all, there are links out there that are self cleaning. Also, you can have the manufacturer install wear discs ahead of time, in between the steel, to offer some added lubrication, if this is required. Obviously, the downside of lubrication is it’s going to pick up … That’s why we want it to be dry. If you put in a W-40 or something like that, it’s going to pick up particulate or debris near it, which is not a good thing.
Mark Z.:
Yeah, [inaudible 00:54:57] on the issue. Yeah.
Mary:
Great, and I think we have time for probably one more question, so let’s finish off with a question about the height. Can you get away with using a normal mounting height and a long travel at slower speeds?
Mark C:
Well, you can get away with it. The problem is that it’s not so much speed, as acceleration that’s going to kill you with the mounting height. Velocity … Go on, Mark, please.
Mark Z.:
Yeah, I think the answer there would be maybe, it depends on the curve height of the track as well. As you get a higher or a bigger curve height, the sag or the critical sag tends to get accelerated. If you have a smaller curve height, say ten or fifteen inches, that’s a lot less stress on the chain, versus a thirty inch that has to come down and sag on itself. I would say that depends. Like you said, Mark, I think in certain applications, you can get away with it, but again, you’ve got to pay attention to speeds and the mounting height.
Mary:
Wonderful. Thank you guys both for being here, and I think that’s about all the time we have. Thank you everyone for attending this great webinar from Design World, and to Mark and Mark from Dynatect for a great presentation. This presentation will be emailed to everyone later today, and will also be available at www.designworldonline.com and have a great day! We thank you for joining us! Bye-bye.
Mark C:
Thank you very much for having us. Bye-bye.
Mary:
Thank you.
Filed Under: Cables + cable management, Flanges • supports • mounts • brackets • hinges, Motion Control Tips
