Taboos against cannabis continue to go up in smoke, which has meant the rapid ascent of an entirely new industry.
It’s also meant proliferation of new automated systems and machine designs for all stages of cannabis production — including growing, harvesting, processing, testing, packaging, and distributing of marijuana and hemp-based goods to satisfy demand.
Before we detail these technologies, it might be helpful to review some basics about the plant itself.
You see, cannabis includes the two subspecies of indica and sativa; psychoactive marijuana strains come from both subspecies, while all hemp strains — incredibly useful in their own right — come from the latter. Hemp is hemp and not classified as a marijuana strain when it’s less than 0.3% of the intoxicant tetrahydrocannabinol (THC) by dry weight, a distinction considered arbitrary by some. Marijuana has THC concentrations of 15% to 40% in most cases.
Despite their various applications, all of these plants were (until recently) illegal to grow or transport. Many states have since passed laws on permitting marijuana … and with the January 2019 U.S. Farm Bill now law, hemp is no longer listed as a Schedule 1 narcotic at all … “and will reinsert itself as one of the most useful plant species on earth,” said Ag t3 Holdings president and CEO Ed Horton.
Ag t3 Holdings is a consultancy that aims to support the U.S. hemp market not for production of the plant’s famously strong and durable fibers, but rather for its cannabidiol or CBD oil. Largely available in states that have legalized medicinal applications of cannabis, CBD oil may reduce inflammation and the effects of anxiety, ADHD, epilepsy, Crohn’s disease, asthma, and glaucoma. Many of these medicinal benefits overlap with those attributed to THC, though CBD has no intoxicating effect. In fact, some research indicates augmented (synergistic) benefits when THC and CBD are consumed together … especially when other cannabis terpenes and flavonoids as well as cannabigerol, cannabichromene, cannabidivarin, and tetrahydrocannabivarin naturally occurring in the plant are also present.
Current approaches to grow hemp — outdoors using relatively traditional means of farming — are often far different than those for marijuana. (Skip to this feature’s section on harvesting for more on technology aimed at maximizing hemp crops’ profitability.) In fact, marijuana cultivation is increasingly done within secure greenhouses or growrooms in fully isolated buildings, especially for large-scale commercial operations.
Growing cannabis in modern ways
Cannabis-industry investments reached $13.8B last year to quadruple those of just two years ago, according to Viridian Capital Advisors. Many new operations leverage automated farming and advanced horticulture technologies, which are seeing their own staggering levels of investment and adoption. That’s according to venture-capital platform AgFunder Inc., which connects agriculture entrepreneurs with investors (and publishes its data at agfundernews.com).
One iteration is the use of greenhouses with automated plant-tending systems. “I can’t say whether we’ve provided engineering support to facilities for cannabis-related automation, only because we sell via distribution channels and don’t always know who end-customers are,” said Jonas Proeger of Trinamic Motion Control. “However, we do know that our PANdrive smart mechatronic solutions are used for automation in agriculture. A Dutch company called Ridder uses them for the automation of vents in livestock stables and greenhouses.”
Proeger also said that his company sees an uptick in precision-agriculture applications.
“These are systems where single plants are supplied with the appropriate amount of water and fertilizers … and unproductive plants or branches are automatically weeded out. Many such operations are still in their research state, but there is a rising trend here,” he added.
In fact, a third of today’s marijuana production is indoors … and the percentage is higher in cooler places such as Colorado and Canada. These growroom settings often house precision hydroponic systems that wash plant roots in nutrient-titrated solutions; along with careful control of the plant environment, this induces growth that’s far faster that soil-based cultivation … and generally yields larger and healthier plants as well.
“One interesting application in cannabis automation is the use of IP65-rated motors in the wet environments of hydroponic nutrient systems,” said Josh Burns, northwest region sales manager for Applied Motion Products.
Another form of precision agriculture is aeroponics — supported by integrated hardware and controls from AEssenseGrows, based in Sunnyvale, Calif. Read our uncut interview with Phil Gibson, a V.P. at AEssenseGrows in coming weeks on designworldonline.com.
Aeroponics is a technique for growing plants in a misted-air environment sans soil or other medium. That’s in contrast with hydroponics, which uses water baths and (in some cases) a small amount of water-retaining medium to support plant roots. Benefits include cleaner operation and more control over the solution makeup that mists over the plant roots for fastest possible growth.
So what’s the catch?
“Aeroponics requires complex controls and sensors to monitor nutrient percentages and guarantee they’re sprayed out at the right rates … and maintain the correct amount of oxygen in the root zone to allow photosynthesis. Plants are funny … they’re upside down — roots need oxygen, and the canopy needs carbon dioxide,” explained Gibson.
Within enclosed growhouses, plants absorb lots of carbon dioxide from the air and turn it into oxygen. Plants use oxygen at their roots for absorbing salts and water and create carbohydrates. Those carbohydrates then go up into the canopy to support photosynthesis using light energy and carbon dioxide. This helps create more complex sugars and structure for the plant … which in turn spur growth. Then the plant aspirates water and oxygen into the atmosphere.
Manual approaches won’t cut it: These biochemical processes necessitate quick and precise regulation of the environment — including the aeroponics of the root zone and the oxygen, carbon dioxide, moisture, temperature, and light energy affecting the plant canopies.
“Our AEssenseGrows AEtrium system optimizes all these processes — concurrently monitoring all disparate parameters with sensor arrays to deliver exactly what plants need. It controls actuators to adjust conditions and automated peristaltic pumps to inject nutrients at precise levels, right when they’re needed. One challenge is that because plants grow so fast with aeroponics (going through photosynthesis so quickly) they can deplete a growroom of carbon dioxide within an hour. In addition, the plants aspirate water so quickly that the growroom becomes a jungle — reaching 90% humidity almost immediately,” noted Gibson.
So the AEssenseGrows system also triggers automatic injection of carbon dioxide into the growroom to keep pace with the photosynthesis and growth process. Other functions include dehumidification and integration with growhouse HVAC functions for heating, air conditioning, air purification, airflow management, and temperature management. Typically, the automated system holds growhouse conditions to 68° and 72° and a thousand parts per million carbon dioxide at 40% humidity with 1,000 PPFD light intensity at the canopy level.
“Everyone at AEssenseGrows is an engineer, and we’re comfortable with this industry because of our vast experience in electronics, control systems, and the development of software environments,” said Gibson.
In fact, Gibson’s own efforts beginning in 1995 at National Semiconductor has informed his involvement in new user interfaces and websites to facilitate data access and system control. That includes the AEssenseGrows Guardian Grow Manager tool that imparts IoT functionality and lets managers remotely monitor grow environments from a laptop or mobile device … and even execute control over electromechanical systems to make adjustments as needed.
Where controls, relatively modest actuators, sensors, and software dominate automated grow settings, proper motion designs are at the heart of cannabis transplanters, harvesting robots, and automated destemming and bucking equipment. Consider bucking — the process of removing marijuana buds or flowers from their stems. Vancouver, Canada-based Shearline is a designer and manufacturer of buckers as well as trimming machines.
“The legalization of marijuana in the U.S., Canada, and the rest of the world has fueled a massive shift in the methods used to grow, harvest, and process cannabis plants,” said Shearline head of research Ryan Hall. Such operations have always been far more difficult than the uninitiated might assume.
Read more about vertical farming that’s helping operators grow better-quality cannabis (and an array of other crops) more efficiently in this article: Cannabis cultivation leverages modular automation stations. As Michael Giunta of Macron Dynamics explains, large-scale cannabis farming is often indoors and highly automated. In some arrangements, movable walls enter and exit stations serviced by one sophisticated robot that executes several plant-management tasks.
“In 1997, after four frustrating years of R&D, I introduced the first machine capable of trimming excess leaf off flowers on all strains of marijuana,” added Hall. Properly setup and operated, this electric-motor-driven machine produces results almost identical to those of hand-trimming methods historically used in processing flower for public consumption — but at speed 10 to 20 times faster.
Since then, Hall has continued work to improve all aspects of this equipment and other automated machinery.
“The ability to develop and test concepts in a totally open and cooperative manner with manufacturers of motors, drive systems, and most importantly, PLC-controlled VFDs, has enabled amazing options to dramatically improve our machines’ efficiencies … and reduce manual labor even further,” said Hall.
One challenges Shearline has addressed with these motion technologies is that of trimming many different marijuana strains — all with unique structures and densities. Each strain requires different and varying levels of trimming-machine drum speed, tilt, and angle; suction; input feed rate; and cutting-system speed and rotation.
Large-scale producers are now demanding the automation of other cannabis processing tasks as well. “These tasks include bucking of buds from the stalks … as trimming machines can’t perform this process — yet. Industrial-scale feeding of trimming machines is another task we’ve automated with our system offerings. These allow for a consistent flowrate to output uniformly trimmed product … and further reduction of manual labor,” Hall explained.
“Here, separation of trimmed material is required prior to passing through the impellers of the blowers running at 3,600-rpm to ensure sufficient suction. This serves to preserve the quality of trimmed leaves, which have become valuable in their own right for use in extractions,” Hall of Shearline continued.
All the machines’ components are food-grade electroless nickel plated or electropolished stainless steel for compliance with strict local regulations.
“Another design collects fine particles to ensure the trimmer maintains the suction so critical to its consistent operation. These particles would otherwise clog outlet filters on the machine that ensure the cleanliness and safety of the surrounding work environment. In fact, particle collection also minimizes the time and labor required for cleaning the equipment.”
This and other equipment to process marijuana plants (and those from OEMs including Twister Trimmer, GreenBroz, and Munch Machine) is well developed and commercially available — employing variable-speed motors to adapt to the infeed of wet and dry plants; HMIs for allow coordinated conveying and manual tasks; and even SKADA integration and IIoT connectivity for remote diagnostics in some cases. In contrast, machinery to make the most of hemp harvests have a way to go.
Hemp is incredibly useful for more than just its CBD. Its fibers have imparted strength and durability to clothing, paper, and construction materials for thousands of years; hemp seeds (high in omega-3 fats and antioxidants) are a versatile health food; and woody portions of the plant can serve as biofuel or in hempcrete (for insulation and paneling applications). One challenge is that hemp stalks’ toughness makes it fairly difficult to process. Plus, it’s been illegal for so long, there’s little infrastructure to handle and distribute the raw material for processing into end products.
One key step in the treating of hemp for non-food or supplement uses is decortication (debarking) to remove stalks’ outer cortex to expose soft bast fibers used in textiles as well as the stalks’ thick woody shives or hurd cores. In the U.S., Hemp Inc. in North Carolina is the sole commercial hemp decorticator. But soon, new pieces of mobile equipment could serve the industry for this function. Edmonton, Canada-based Natural Fibre Technologies recently released a mobile hemp and flax decorticator; Formation Ag (through a number of partnerships) has also begun production of this specialty mobile equipment.
If successful, their efforts could address the current disconnect between hemp producers and those looking to make non-CBD goods out of the plant. But key to effective mobile-decorticator design is that they be self-feeding units … as viable hemp-fiber farming necessitates the harvesting of many thousands of acres. Check out the Motion Trends piece on electric actuators for details on where linear-motion components and IoT functionality are improving heavy vehicles and off-highway machinery not unlike self-feeding decorticators.
Technologies in cannabinoid extraction and testing
Cannabinoids such as THC and CBD are often extracted from marijuana and hemp stalks for more versatile application in edibles, drops, and vaping products. Extraction is through use of a solvent in the form of low-temperature CO2 at high pressure; ethanol; olive oil; and butane or hexane.
As Burns of Applied Motion Products explains, many cannabis processes are similar to others in food and consumer packaged goods. “However, there are some areas of which we weren’t initially aware when entering the cannabis automation market. For example, one method of extracting CBD from the plant relies on the use of high-grade grain alcohol or ethanol, which is highly flammable. For an application such as this, we must supply specialized motion-control solutions — including those certified for use in hazardous locations. Such offerings include our HX56-100 stepper motor and STAC6-Q-H stepper drive.”
Motor makers address the challenges of yet other THC and CBD extraction methods.
“Empire makes high-performance cryogenic motors among many other special-use motors,” said Richard Halstead, president of Empire Magnetics. “One motor design works in a machine for the extraction of cannabinoids at extremely cold temperatures.”
As the most widely used illegal drug, a large body of knowledge has been accumulated about the effect of cannabinoids — including those for medicinal purposes. But this information was not collected using traditional methods (by pharmaceutical companies or other medical entities) so companies are now struggling to normalize the process of extracting these compounds in a safe, controlled, industrial scale process.
“To date, the preferred extraction process uses liquid carbon dioxide,” continued Halstead.
“This material provides a high extraction rate without leaving residue in the compounds. The catch is that because the process takes place at high pressure and temperatures of about -90° C, special equipment (including electric motors to operate the pumps, agitators, and other necessary motions) that can operate under these conditions is required.”
So Empire Magnetics designed a solution that addresses the issue with a combination axial-gap motor and a magnetic coupling. “To avoid contamination, the motor windings (stator) are sealed in a welded stainless-steel containment that prevents intrusion of moisture that would turn to ice. The rotor contains features for the agitator and turns on ceramic bearings. These ceramic bearings are lubricated by the liquid CO2. The stator materials and construction were made for the wide range in temperature the motor sees … and because they’re not in contact with the fluids in the tank, there were no constraints on the material choices,” explained Halstead.
“The motor design of this extractor is highly engineered … and in fact, Empire Magnetics regularly designs and manufactures motors for use in these types of extreme conditions and temperatures — including motors tested by the USAF at 24 Kelvin — which is -249° C,” he added.
Packaging and distributing cannabis edibles and medicinal products
Much of the final packaging of cannabis products borrows from the medical-supply and food and beverage industries. However, the labeling of THC and CBD-infused edibles requires a unique combination of dietary as well as dosing information; states such as California regulate this labeling with rules that are much like those for alcohol and tobacco.
In addition, the pouching and wrapping of cannabis products must be child-resistant; tamper evident with a tearing element or pop-up indicator that shows when a product has been opened; and resealable for multi-serving products. In addition, the packaging must be nontransparent (to hide the appearance of the contents); and indicate the THC and CBD in mg per serving.
Said Burns of Applied Motion Products: “We’ve seen an increase in the adoption of automated systems for cannabis-related production and packaging. Many of the applications are similar to existing applications in food and consumer goods … and employ machines for sorting, weighing, filling, capping, sealing, and other traditional forms of packaging.” Other packaging equipment relevant here includes that for candy production; labeling; and wrapping and case packing.
For these applications, Burns added that Applied Motion Products can specify standard motion-control solutions … the same motors and drives that have been in use for years in packaging machinery.