For manufacturers looking for large plastic components, the choice between injection molding and vacuum forming comes up quite often. Both processes are great, but they don't always compete on the same terms.

Injection Molding

This process works by forcing molten plastic into a closed steel mold under high pressure. The process gives you highly detailed, consistent parts and handles complex geometries well. The drawback when it comes to injection molding however is tooling cost. Steel molds are expensive to design and machine, and lead times reflect that. For high-volume production, those costs spread out but for lower volumes or larger parts, they rarely do.

Vacuum Forming

This process takes a different approach. A plastic sheet is heated and drawn over an open mold using vacuum pressure. Tooling is typically machined aluminum, which costs a lot less than steel and machines faster. For large parts such as covers, enclosures, housings, vacuum forming produces solid results at a fraction of the upfront investment.

Injection molding shows better tolerances and handles undercuts and internal features more readily whereas vacuum forming works best when the geometry is relatively open and cosmetic requirements are moderate. However, the gap narrows considerably with well-designed tooling. A properly engineered vacuum form mold, machined to the customer's 3D specifications and inspected through a documented process, produces quality parts.

For manufacturers in Michigan and surrounding regions looking at vacuum forming mold design, American Tool & Engineering engineers molds to customer specifications using SOLIDWORKS CAD, 5-axis CNC machining, and Faro Arm scanning for dimensional verification. Get in touch with us for more details.