Plastic Prototype Machining & Metal Prototype Parts — One CNC Platform
JIERCHEN cuts both CNC plastic prototypes and low-volume metal parts on the same in-house machining line, so an engineer can validate a design in ABS or PC and move straight to an aluminum or stainless production-intent sample without changing vendors, drawings, or tolerance standards. All parts are CMM-verified to ±0.01mm against ISO 2768-f.
Get a 24-Hour Quote Compare CNC MaterialsPlastic or Metal: How to Choose
The right prototype material depends on what the part has to prove. Use plastic prototype machining for early-stage fit, appearance, and electrical-layout checks; move to metal prototype parts once the design has to survive load, heat, or repeated cycling. Most projects run both: a plastic round to validate geometry fast, then a metal round to confirm the part will actually hold up in the field.
| Decision Factor | Choose Plastic | Choose Metal |
|---|---|---|
| Priority | Speed, cost, early design review | Strength, heat resistance, production-representative finish |
| Electrical requirement | Non-conductive housings, connectors | Conductive contacts, shielding, grounding parts |
| Weight | Lightweight assemblies, handheld products | Structural or load-bearing components |
| Typical CNC plastic prototypes | ABS, PC, ABS+PC, PMMA, POM, PP | — |
| Typical low-volume metal parts | — | Aluminum 6061/6063/7075, stainless steel, copper, zinc alloy |
For the full engineering-plastic and metal-alloy breakdown, including PTFE, MC nylon, and PEEK, see the CNC material guide. Not sure which way to go? Send us your drawing and we’ll recommend a material before you commit to a full order.
CNC Plastic Prototypes
Most CNC plastic prototype orders run in ABS, PC, ABS+PC, or PMMA (acrylic), with POM and PP covering more specialized fit or chemical-resistance needs. Plastics are the default choice when a part needs to be light, electrically non-conductive, or turned around fast for an early design review.
| Material | Selection Notes | Compatible Finishing |
|---|---|---|
| ABS | Impact-resistant, easy to machine to a smooth surface. Default choice for housings and general-purpose prototypes. | Spray painting, sandblasting, silk-screen printing, electroplating |
| PC | Higher impact strength than ABS, available in optical-clarity grades, tolerates more heat. Used for clear covers and light-guide parts. | Polishing, laser engraving, spray painting |
| ABS+PC | Combines PC’s toughness with ABS’s machinability. Chosen when a structural housing needs extra impact resistance. | Spray painting, sandblasting, silk-screen printing |
| PMMA (Acrylic) | Optically clear, rigid, and takes a polished edge well. Used for light pipes, display parts, and clear enclosures. | Polishing, laser engraving |
| POM (Acetal) | Low friction and dimensionally stable, holds tight tolerances under repeated motion. Used for gears, bushings, and precision-fit components. | Polishing, matte finish |
| PP | Chemical-resistant and flexible enough to support living hinges. Used for chemical-contact parts and snap-fit lids. | Sandblasting, matte finish |
Low-Volume Metal Parts
When a prototype has to prove strength, thermal performance, or a real production finish, JIERCHEN machines it in aluminum, stainless steel, copper, or zinc alloy — the same metal prototype process scales cleanly into a low-volume metal parts run once the design is locked.
| Material | Selection Notes | Compatible Finishing |
|---|---|---|
| Aluminum (AL6061 / 6063) | Lightweight, good general strength, corrosion-resistant, and easy to machine. The default choice for enclosures, brackets, and heat sinks. | Anodizing, sandblasting, electroplating, hairline texture |
| Aluminum (AL7075) | Higher strength than 6061/6063 for load-bearing or structural prototype parts, at somewhat higher machining cost. | Anodizing, sandblasting, hairline texture |
| Stainless Steel | Corrosion-resistant with a hygienic, production-grade surface. Used for medical housings, food-contact parts, and marine-exposure components. | Polishing, electroplating, sandblasting |
| Copper | High electrical and thermal conductivity, easy to machine. Used for electrical contacts, connectors, and decorative trim. | Polishing, electroplating |
| Zinc Alloy | Good castability and dimensional stability at lower cost. Used for connector housings and cast-style prototype parts. | Electroplating, spray painting |
Every finishing option above is detailed on the surface finishing page, including which processes pair well together across plastic and metal parts.
CNC Tolerance & Lead Time
Standard CNC machining tolerance follows ISO 2768-f across both plastic and metal prototypes. Critical dimensions are verified on a Keyence coordinate measuring machine (CMM) to ±0.01mm, and JIERCHEN works from inch-based drawings and ASME Y14.5 GD&T callouts as readily as metric prints.
| Stage | Process | Typical Lead Time |
|---|---|---|
| Validate | SLA 3D printing | 1–3 days |
| Test | CNC machining (plastic or metal) | 3–7 days |
| Pilot | Silicone / vacuum casting (10–50 pcs) | 5–10 days |
| Scale | Steel-mold injection molding | 4–8 weeks |
Quotes are typically returned within 24 hours; parts ship internationally and NDAs are available on request. See how every stage is checked on the Total Quality Control page.
From Single-Piece Prototype to Low-Volume Production
There is no minimum order quantity to start — a CNC plastic prototype or metal prototype can be a single piece for design validation. Once the design is locked, the same part can move into a small CNC production batch, or into steel-mold injection molding when volumes justify tooling. JIERCHEN carries the project across that entire path under one roof, so tolerances, materials, and inspection records stay consistent from the first sample to the production run.
Frequently Asked Questions
Should I choose plastic or metal for my first prototype round?
If you’re validating fit, appearance, or an early electrical layout, CNC plastic prototypes in ABS or PC are usually faster and lower cost. Once you need to prove strength, heat resistance, or a production-representative finish, move to a metal prototype in aluminum or stainless steel. Send us your drawing and we’ll recommend a material before you commit to a full order.
What tolerance can I expect on a CNC prototype?
Standard tolerance is ISO 2768-f. Critical, callout-specific dimensions are verified on our Keyence CMM to ±0.01mm, on both plastic and metal parts.
Is there a minimum order quantity for metal prototype parts?
No. JIERCHEN takes on single-piece prototype orders as well as low-volume metal parts runs, and can carry the same design into steel-mold injection molding once volumes justify tooling.
Do you accept inch-based drawings and GD&T callouts?
Yes. JIERCHEN works from both metric and inch-based drawings, including ASME Y14.5 GD&T callouts, for plastic and metal prototype orders alike.
Can plastic and metal parts from the same order get matching finishes?
Some finishes overlap — spray painting, electroplating, and sandblasting work on both — but a few are material-specific, such as anodizing and laser engraving for metal only. See the full surface finishing page for compatible combinations.
Can you keep my project confidential?
Yes. JIERCHEN signs NDAs on request before reviewing drawings, standard for both plastic prototype machining and metal prototype work.
Tell Us What You’re Building
Send a drawing and target material and we’ll confirm tolerance, finish options, and lead time within 24 hours.
Get a Free QuoteJIERCHEN Enterprise Co., Ltd. · No. 5, Alley 19, Lane 49, Guoqing Rd., Banqiao Dist., New Taipei City 220, Taiwan · +886-2-7728-5122 · sales@jierchen.com.tw · Mon–Fri 08:30–17:30
