Extruded Seals: Cost Drivers
We’re always trying to drive cost out of products and extruded seals are no exception. It’s just that due to the already simple nature of extrusions, we are fairly limited as to how far we can go. But there are a handful of strategies to consider and undertake, especially when it comes to design.
We know the cost drivers because we live and breathe extrusions every day. And we’re glad to share this with you so your extrusions don’t end up costing you any more than they should.
When it comes right down to it, choosing the right material is just as important as getting the design right. In fact, it may be more important as material affects design, manufacturability, part performance, and overall cost.
A key to a successful design is to choose the lowest cost material meeting your part or design requirements. Suppliers of extruded seals can demonstrate the differences between material types and be able to help you choose. As with many plastic manufacturing processes, the use of re-grind helps keep costs low while reducing environmental impact. And most OEM’s allow 50 to 100% re-grind in an extruded seal.
Finally, when a seal application requires more than one material, such as a part that needs a rigid base and a flexible sealing component, choose materials with a strong molecular bond and use co-extrusion to bond them in-process.
The key to good extruded seal design is to keep it simple. And not just because complexity adds cost but because complexity – too thick walls or unnecessary hollows or too restrictive tolerances – actually work against your design. Let’s take closer look at these…
Wall thickness should be as thin as possible and consistent, as inconsistency causes unbalanced cooling and material flow, adding complexity to engineering and production.
Avoid hollows whenever possible, as water can’t be pumped into the tooling that creates the hollow, which causes uneven cooling and adds complexity to engineering and production.
Tolerances should be as generous as possible, as this gives more flexibility to engineering.
Use flow simulation software and FEA studies to get the design right the first time and minimize risk; design changes are expensive after tooling is built!
In addition to good design, eliminating secondary operations also reduces cost and improves repeatability. If your design calls for holes, tabs, etc., use in-line processing as this will reduce labor costs. Also, whenever possible, design mechanical attachments into the part; this reduces the need for additional assembly which, in turn, reduces labor and material costs.
Resources for Engineers
As you can see, the biggest cost-driver is design. Learn more about design and other best practices in our Extruded Seal Design Guide.