Putting it all together: The right assembly for your multi-material designDecember 12, 2014
You’ve settled on the right materials for your new product design, selected for their compatibility, performance, reliability and cost. But what’s the best way to put it all together?
Sometimes, the answer is obvious. But in other cases, you’ll need to carefully weigh the advantages of various assembly options and consider how each might optimize product performance and longevity.
There are for common assembly methods with distinctive advantages that apply to specific products and situations.
- Mechanical assembly is an often-affordable option that enables a wide range of material combinations, as well as easier disassembly for service and repair. Certainly, not all materials can be combined with screws, fasteners, snaps or post and sockets. MRPC has leveraged mechanical assembly to not only solve manufacturing problems but also help clients save on production and labor costs through automated packaging.
- Chemical assembly leverages chemically compatible adhesives to bond two materials. A lighter-weight option than mechanical assembly, chemical assembly creates smooth, continuous surfaces across which stress distribution is more balanced, and which can withstand shock and vibration. Expertise in material compatibility is critical to the success of this approach, as is sufficient testing and experimentation to ensure that a bond will hold.
- Thermal assembly creates strong chemical bonds by melting thermoplastic material together, often resulting in a bond strength nearly equal to the strength of the raw material itself. Like chemical assembly, thermal assembly yields smooth mating surfaces exhibiting well balanced stress distribution. It also enables hermetic seals, to remove the risk of leakage.
- Overmolding, also called multi-material molding, involves molding a material over a previously formed part. The substrate can be nearly any rigid material, such as plastic or metal, but it must have a high enough melting temperature to remain solid during the overmolding. Overmolding creates durable and long-lasting final products, enables automated assembly for reduced labor costs, and enables ergonomic design. However, overmolding can introduce complexity, and the high melting temperature required limits overmolding’s use when working with thermoplastics and thermosetting silicones.
MRPC’s experts can help your team think through assembly decisions as well as material ones, to help you achieve your cost, performance and functionality goals. For more details on assembly methods and MRPC’s experience, download our whitepaper.