Industry
A machine builder may have hundreds of plastic part numbers, each ordered in modest quantities for decades. The challenge is less about any one part and more about keeping all of them available, consistent, and affordable.
Many parts, few of each
The volume is spread thin across a long list.
A packaging machine, a pump skid, or a machine tool carries covers, knobs, handwheels, cable guides, and guards that are each built in small numbers. Many started as machined or fabricated metal because the volumes looked too low for a mold. Over years of production, and years of spare parts after that, the total quantity often makes molding the better choice.
Two things make that work. There is no minimum order quantity, so a part that sells in small lots can still be molded. And the customer owns the tool, so a part that must be available for the life of the machine is not tied to one supplier's plans.
On the machine
Each switch has a different reason.
| Part | Made from before | Why mold it |
|---|---|---|
| Covers and hoods | Bent and welded sheet metal | Vents, clips, and mounts in one part, no painting |
| Handwheels, knobs, and levers | Cast or machined metal | Lighter, cooler to touch, with a metal hub molded in |
| Bushings and wear pads | Bronze | Runs without grease in many cases, will not seize |
| Control and sensor housings | Die cast or bent metal boxes | Integrated mounts and a seal groove, radio signals pass through |
| Guards and windows | Mesh or sheet metal | Clear polycarbonate lets operators see the process |
Shop floor
Machines live in fluids that attack some plastics and leave others untouched.
FAQ
Look at the life of the part, not one year. A cover built into every machine and sold as a spare for many years often adds up to enough parts to pay back a tool. DFM and the instant quote show where that line falls.
Yes. A family mold can produce knobs, clips, and caps of similar size and resin together, which lowers tooling cost across a list of low volume parts.
The customer owns the tool and can request it at any time, so spares can still be made years later.
Yes. Insert molding puts metal hubs, threaded inserts, and bushings into the part as it is molded, and inserts can also be installed after molding.
Keep reading
Machine parts, metal replacement, and shop floor resins.
Clear and solid guards.
Safety guardsHandwheels and control knobs.
KnobsWear parts without grease.
BushingsWhere the switch pays off.
Metal to plastic conversionHow very large covers are made.
Structural foam moldingDuty cycles across the sector.
Industrial and transportationEvery sector page in one index.
Industries hubNext step
Upload CAD for the parts you are considering, with yearly and spare part quantities and the fluids they see. We will point out which ones suit molding and which can share a tool. NetProto manufacturing is ISO 9001 certified.
