For OEMs that apply laminate films to metal parts or apply coatings to as decorative finishes, the in-house manufacturing process requires a significant investment in equipment, plant floor space, and ongoing maintenance for what can be a very temperamental process.
Not only that, but failure to precisely control what can be a very temperamental process can lead to laminates which do no bond properly or wrinkle, leading to excessively high scrap rates and even product returns.
For this reason, OEMs are increasingly outsourcing the application of laminate films (Figure) to experienced coil coaters who can provide several alternatives: steel, aluminum or other metals in coil or sheet form with pre-applied (dry) adhesive; or fully laminated product that eliminates in-house processing altogether.
The use of laminate applied to metal to fabricate parts or products is widespread throughout manufacturing. Decorative finishes provide the look of stainless steel, brushed copper, and wood grains, as well as a variety of colors, imprints, and a range gloss levels. Laminate films can also serve a functional purpose by providing scratch or chemical resistance.
Applying laminates to metal requires multiple steps. First, the metal is prepared by chemically cleaning and pre-treating. A liquid adhesive or film laminate is then applied to the metal and cured in an oven. The laminate film is then bonded to the metal as the adhesive coated metal exits the oven and the laminate is fed into nip rollers to join the laminate to the adhesive. The laminated metal is then cooled.
In each step of the process, there can be challenges which can lead to poor bonding or delamination. Some of these include issues with bonding caused by the cleanliness of the metal, improper application of the adhesive, or insufficient oven temperatures. The result is high scrap rates, with consequent product returns.
One option for OEMs is to turn to experienced coil coaters who can pre-apply B-stage adhesive to virtually any metal substrate. The B-stage adhesive is designed to reactivate and cure within a specific temperature range to bond the laminate. This eliminates several steps and can lead to a higher quality laminate bond.
An experienced coil coater monitors their own quality, and has the ability to cut laminated coil to just about any size, ready for stamping, forming or other finishing operations. This can eliminate several additional in-house steps and simplifies the process of maintaining an inventory of laminated metals in different sizes.
Experienced coil coaters are also better equipped to handle difficult adhesion challenges, sometimes with the ability to deliver custom formulations and provide other advice about the lamination process.
One example is adhesives formulated to be more “forgiving” in terms of temperature curing ranges. This can help OEMs that have challenges with oven temperature or consistency across the width of the coil.
Popular laminate films like TPO (Thermoplastic olefin) are also notoriously difficult to bond to metal. TPO can refer to materials such as polypropylene (PP), polyethylene (PE), block copolymer polypropylene (BCPP) and others.
A good time to consider the transition to outsourcing lamination is for plants that are utilizing aging equipment that can be time-consuming and costly to maintain, or when scrap rates or performance issues with in-house laminating are excessively high.
Once equipment is 10 to 15 years old, more maintenance is needed. At this point, outsourcing the lamination process might be more cost-effective than upgrading the equipment.
Filed Under: Materials • advanced, Rapid prototyping