How to Leverage Low-Volume Injection Molding
Whether you’re designing a lifesaving medical device or a high-flying drone, investing $50,000 or more—often much more—in high-volume steel tooling is an inherent financial risk that comes with a move to large-scale production. Compounding the risk is months of idle time as you wait on your steel tool to be ready when you could be iterating part design or even producing products that generate revenue. There is a better way: on-demand manufacturing.Get more news about
Low Volume Plastic Injection Molding,you can vist our website!
At Protolabs, our on-demand, low-volume production offering with injection molding—which uses aluminum tooling—is a fast, cost-effective way to produce hundreds of thousands of end-use molded parts.
Use this process as the primary production method for your products. On-demand manufacturing is also an excellent way to move from prototyping to low-volume production for molded parts. We may have “Proto” in our name, but we are actually a full-service manufacturing provider. Low-volume runs can also help you validate part design and manage inventory overhead with production of parts only when demand dictates. In addition, even if you need to eventually shift into mass production of plastic parts, you can still use our cost-effective aluminum tooling as a bridge before committing to a capital expense with steel tooling. Finally, this on-demand approach also optimizes your supply chain, making it more adept in managing demand volatility.
This design tip outlines our quoting system, which has new upgrades; reviews several design considerations that can improve injection molding part design for on-demand manufacturing; and briefly looks at how this on-demand approach can help manage your supply chain.
First things first. Part designs can be uploaded directly online, day or night, seven days a week at Protolabs. An interactive quote, which really serves as the keystone of our digital manufacturing platform, is typically sent within hours. Once you receive a quote, you can set primary manufacturing requirements such as desired material, surface finish, and initial production quantity. This free, automated, design for manufacturability (DFM) analysis is provided with every quote. This includes recommendations on how and where to modify part geometry to improve mechanical strength, reduce sink, adjust wall thicknesses, and other considerations that can improve cost, production, and tool life. In addition, recent upgrades to our system have integrated our on-demand manufacturing option. You now can find prototyping and production options for injection molding under one quoting roof. Also, our new Price Curve tool compares prototyping vs. on-demand manufacturing options so you have full visibility to total cost of ownership on molded parts throughout the product life cycle.
You can also get free design help with our Consultative Design Service (CDS) if your CAD model isn’t quite suited to our system, or you need help getting it to meet our guidelines. CDS will help you update your CAD model to address the manufacturability feedback you received with your quote. One of our injection molding applications engineers will work with you on your part design to ensure your part is moldable.
A common mistake made with injection-molded parts is calling out a better surface finish than is necessary for part function. A very smooth SPI-A2 (read: shiny) finish, for example, requires mold cavity surfaces to be hand-polished with diamond buff to 1-2 Ra. This drives up the cost of mold manufacturing and increases lead-time. The least expensive part finish is a non-cosmetic PM-F0, an as-machined surface that will probably show some tool marks. In between are two options such as a 10-12 Ra SPI-C1 finish, made using a 600 grit stone, or a PM-T1 bead-blast textured finish. Other finishes are available as well. Use the lowest-cost finish that is compatible with your application.
Use Draft for Easier Part Ejection from Mold
Injection-molded parts need draft for the same reason that ice cubes aren’t true cubes. Ice cube trays are angled, which create ice cubes with tapered edges (or draft) so the cubes release easily from the tray. Molded parts should, too. Draft allows for easier ejection of the part.
Scale Wall Thickness Up and Down
Wall thickness is important. Imagine you're designing a simple box. At first glance, thick walls might seem like a good way to keep the box's contents safe. But the plastics used with injection molding are, well, plastic.
Walls thicker than what is recommended for the particular thermoplastic family being used will be subject to warp and sink during cooling. A general rule of thumb for wall thickness is somewhere between 0.040 in. to 0.140 in. (1 to 3.5mm), applied consistently across the entire part.
