Lately it’s been pretty easy to think about the “what happens if…” scenarios that may not have been a thought during your last injection molding project. The current economic climate mixed with international relations, may be changing the face of how we do business on certain assembly projects. There are now risks associated with assembly projects in injection molding that may not have been there 5 or 10 years ago. The supply chain for components never missed a beat, and now every week may be an inventory and supply check to ensure business can stay running. If you’re contemplating a new assembly project with injection molding, you may want to include these topics at your next roundtable:
Flexible Material Options
Before you finalize your next part assembly design, you’ll have a list of potential resins to consider. Some will be a perfect fit for the dimensional tolerances needed, the durability and structural strength to meet customer demand, and the corrosion resistance to survive the harshest environments. What happens if that perfect resin isn’t easily available anymore? There are 1,000s of plastics to choose from, and each component in your final assembly should be injection molded from a material that is readily available or has a secondary option for quick replacement if needed. Your secondary resin option should be similar in temperature tolerance to prevent failures in the field. It also needs to take into consideration the overall performance characteristics required for the design. Will it see shock loads in the customer’s hands? Will it survive under extreme tension or compression while in service in the field? The smallest details can and will affect which materials are selected as primary and secondary options.
Create a Flexible Assembly Process
Creating your initial part assembly process is part of the lifecycle of the new product. What happens if your perfect assembly is disrupted because of a missing component or a volume fluctuation? For every step in the assembly process you’ll want to review what is required, determine if it can it be simplified, and can the step be bypassed if a component is missing. The microchip shortage that has affected global manufacturers should be an example that needs to pay forward as an opportunity for risk mitigation. If a component, whether a fastener or assembly part, comes up short can you still manufacture product without it? If your assembly process will have to shut down, can your product be redesigned to accommodate a shortage? Will that redesign also incorporate ways to reduce potential mistakes?
Using Datum Strategies & Alignment Features to Reduce Errors
Your design team has a primary focus to make your assemblies extremely intuitive to put together. The current workforce is constantly evolving, and some days you may not have a full staff of trained employees on the assembly line. What happens if you have 50% of your regular employees, and the other 50% are new employees? A properly designed datum scheme indicates which feature of an assembly to connect first, second, third, and beyond. When it references assembly, a datum scheme may translate into hole sizes being round, oblong, or oversized based on their sequence in the assembly process. There may also be features on the components to ensure they can’t be assembled incorrectly before moving to the next workstation.
Design with Differing Attachment Options
Your new injection molding assembly design may need to attach multiple components together. That could be with fasteners for replacement options, or with a permanent solution. What happens if you use fasteners, but your ideal choice comes up short on this week’s inbound shipment? You may need to substitute another fastener with a different head shape, a different length, or a different thread pitch to keep running. Is your design flexible to accommodate all of those secondary options? Would your assembly process be able to utilize a different shaped fastener with a quick tooling change? Having a flexible design that can accommodate some changes will be beneficial, even if you don’t need to worry about “what happens if…” very often.
Your design may incorporate a permanent attachment option such as ultrasonic welding or heat staking. What happens if your equipment has a malfunction and replacement parts aren’t readily available? Can your design incorporate another attachment method like solvent bonding as a secondary option as a temporary countermeasure? Will your resin(s) allow for a secondary attachment option? You may need to ensure the melting temperatures of joining plastics are within approximately 30°F of each other, and each component should have an appropriate joining amount of material to melt or bond together.
Designing your plastic molding assembly project for the “what happens if…” scenarios hasn’t been a common practice in the past. Today’s economy needs to incorporate a complete Design for Assembly (DFA) methodology to identify the assembly method for a product and mitigate the potential risks. Computer Aided Design (CAD) software can include tools to aid designers in prediction of problems, but a lot of the industry know-how will come from years of experience. SEA-LECT Plastics has an elite staff of designers that specialize in design for part assembly and risk mitigation. Our staff keeps us in the top ranking for turn-key manufacturers that can offer industry-specific design options, material selection for competitive cost and performance, and turn-key assembly options to produce it in-house in Everett, Washington. If you have a new idea, call us (425) 339-0288 or email us at email@example.com. We can offer you advice on the best technology to use, the best materials to meet your product demands, and how to navigate through each development stage with ease.
Matthias Poischbeg was born and raised in Hamburg, Germany. Matt moved to Everett, Wash., after finishing his bachelor’s degree in business in 1995 to work for Sea-Dog Corporation, a manufacturer, and distributor of marine and rigging hardware established in 1923.
In 1999, Matt took over the reins at Sea-Lect Plastics Corporation, a sister company of Sea-Dog and a manufacturer of plastic injection molded products with an in-house tool & die shop. Matthias Poischbeg is also a contributor to Grit Daily.