Plastic Injection Molding & CNC Machining Services from China — A Contract Manufacturing Buyer's Guide

Custom plastic injection molding and CNC machining services are the foundation of contract manufacturing for medical device companies, consumer electronics OEMs, automotive Tier-2 suppliers, industrial equipment manufacturers, and product startups worldwide. The category includes complete service offerings: tooling design and manufacture, prototype CNC machining, plastic injection molding production, post-processing (assembly, painting, decoration), and quality assurance. China is the world's largest contract manufacturing hub for these services, with thousands of factories at every quality tier from prototype-shop scale through automotive Tier-1 OEM scale.

This guide covers the Kemal Manufacturing service portfolio — plastic injection molding (medical-grade clean-room through high-volume consumer), injection mold tooling design and manufacture (P20, H13, S136 mold steels), CNC machining (3-axis, 5-axis, multi-spindle), rapid prototyping (CNC, 3D printing, vacuum casting), and complete contract manufacturing including assembly and packaging. Real product images linking back to the supplier's catalog at kemalmfg.com.

Product range — actual catalogue images

The product images below are hosted on the manufacturer's official website (kemalmfg.com) and link directly to the manufacturer's catalogue. Click any image to view the full specification page in a new tab.

Clean-room class injection mold tooling — multi-cavity steel mold for medical-grade and high-precision plastic parts.

View on supplier site →

Plastic injection molding production floor — automated multi-machine production with HETINC and DINVO branded equipment.

View on supplier site →

Rapid prototyping via CNC machining — aluminum impeller machined on multi-axis CNC for prototype validation.

View on supplier site →

CNC machining production — precision metal parts machined to spec with ISO 9001 / ISO 13485 quality standards.

View on supplier site →

Service portfolio overview

Service	Description	Typical applications	Pricing model
Injection mold tooling	Mold design, manufacture, validation	Production tooling for plastic parts	USD 3,000-150,000 per mold
Plastic injection molding production	High-volume part production	Consumer products, medical, automotive	USD 0.05-15.00 per part (volume-dependent)
CNC machining (3-axis)	Standard milling and turning operations	Prototype and low-volume metal parts	USD 1.50-45.00 per part (size/complexity)
CNC machining (5-axis)	Complex geometry single-setup machining	Aerospace, medical, complex prototypes	USD 8.00-180.00 per part
Rapid prototyping (CNC)	Fast turnaround machined prototypes	Design validation, fit testing	USD 50-1,500 per prototype + shipping
Rapid prototyping (3D print)	SLA, FDM, SLS for prototype parts	Form/fit validation, concept models	USD 25-450 per prototype
Vacuum casting (urethane)	Low-volume polyurethane parts from silicone mold	10-50 piece bridge production	USD 25-380 per part + tool USD 350-2,500
Sheet metal fabrication	Laser cutting, bending, welding	Enclosures, brackets, custom assemblies	USD 5-280 per part
Die casting	Aluminum/zinc/magnesium pressure die casting	Heat sinks, automotive, consumer hardware	USD 0.50-25.00 per part + tool USD 8,000-95,000
Post-processing	Painting, plating, anodizing, EMI shielding, assembly	Production-ready finished parts	Per-process pricing

Injection mold construction tiers

Mold tier	Steel grade	Production lifetime	Best applications	Cost premium vs base
Prototype mold (aluminum)	Aluminum 7075	500-5,000 shots	Validation prototypes only	30-50% of P20 cost
Bridge production mold	P20 pre-hardened	50,000-300,000 shots	Initial market launch, low-volume production	Base reference (100%)
Standard production mold	P20 + hardened inserts	200,000-500,000 shots	Consumer products, mainstream production	+15-30% over P20 base
Premium production mold	H13 hardened tool steel	500,000-1,500,000 shots	Automotive, high-volume consumer	+40-60% over P20 base
High-precision mold	S136 stainless / DC53	500,000-1,000,000 shots	Medical, optical, food-contact, electrical	+50-80% over P20 base
Mass-volume mold	H13 + multi-cavity hot runner	1,000,000+ shots	Massmarket consumer, packaging	+80-150% over P20 base

Mold tier selection drives part economics over production lifetime

The wrong mold tier creates expensive operational issues: (1) UNDER-SPECIFIED MOLDS — fail prematurely, requiring expensive re-tooling mid-production; (2) OVER-SPECIFIED MOLDS — inflate initial capital cost without proportional benefit. Match mold tier to expected production volume: under 50,000 parts lifetime → prototype/bridge mold; 50K-500K → standard P20; 500K-1M → premium H13; >1M → mass-volume tier with hot runner. For uncertain demand, P20 standard is often the right balance — it can handle 200-500K parts adequately while staying affordable. For medical/food-contact applications, S136 stainless is mandatory regardless of volume due to corrosion-resistance requirements. Reputable mold makers like Kemal Manufacturing recommend tier based on customer's actual volume forecast and application requirements.

Material selection for plastic injection

Material	Properties	Common applications	Cost ratio vs ABS
ABS (acrylonitrile butadiene styrene)	General-purpose, good impact, easy to mold	Consumer products, electronics housings, automotive interior	1.0× (baseline)
PP (polypropylene)	Chemical resistance, lightweight, food-safe	Containers, automotive, appliance components	0.7-0.9×
PC (polycarbonate)	Optical clarity, high impact resistance	Lenses, electronic enclosures, automotive lighting	1.5-2.0×
PC/ABS blend	Combined strength + impact + processability	Premium consumer electronics, automotive interior	1.3-1.8×
HDPE / LDPE	Chemical resistance, low cost	Packaging, containers, plumbing	0.5-0.8×
POM (acetal / Delrin)	Low friction, high stiffness, dimensional stability	Gears, bearings, mechanical parts	1.6-2.4×
Nylon (PA6, PA66)	Tough, heat-resistant, can be glass-filled	Automotive under-hood, mechanical parts	1.4-2.2×
PEEK (polyetheretherketone)	Premium engineering plastic, high temp/chemical resistance	Aerospace, medical implants, semiconductor	30-80×
PEI (polyetherimide / Ultem)	Inherent flame resistance, high temperature	Aerospace, medical, electrical insulation	15-40×
TPU / TPE (thermoplastic elastomer)	Soft, flexible, rubber-like	Grips, seals, soft-touch surfaces	1.2-1.8×
Medical-grade PC / PE	USP Class VI, FDA-compliant	Medical devices, drug delivery	2.0-3.5×

Quality certifications and applications

Certification	Application area	Required for
ISO 9001:2015	General quality management	Most B2B contract manufacturing
ISO 13485:2016	Medical device quality management	Medical device contract manufacturing
IATF 16949	Automotive quality management	Automotive Tier-1 / Tier-2 supply
AS9100D	Aerospace quality management	Aerospace contract manufacturing
ISO 14001	Environmental management	Sustainability-focused customers
FDA registration	Medical device manufacturing	FDA-regulated medical products
USP Class VI	Biocompatibility (plastics for medical)	Medical implants, drug delivery contact
UL listing	Electrical safety	Electrical/electronic enclosures
FCC certification	Electromagnetic compatibility	Electronic products with RF emission
CE marking	EU market access	Most products entering EU
RoHS	Restricted substances	EU and most international electronics

Pricing brackets — typical contract manufacturing

Customer type	Annual production volume	Typical contract structure
Startup / prototype validation	100-2,000 parts	Per-order pricing; CNC machining or short-run molding
Bridge production / Kickstarter	2,000-50,000 parts	Bridge mold + production; per-part discount with volume
Mid OEM / consumer products	50,000-500,000 parts	Standard P20 mold + per-part production; 6-12 month forecast
Medium OEM	500,000-2 million parts/year	Premium mold + framework agreement; quarterly reviews
Tier-1 / mass production	2+ million parts/year	Multi-cavity hot-runner mold + dedicated production line

Order workflow — contract manufacturing engagement

Design submission — provide 3D CAD files (STEP, IGES, or native format), 2D drawings with critical dimensions and tolerances, material specification, surface finish requirements, intended quantity
DFM (Design for Manufacturing) review — supplier engineering reviews design for manufacturability; typically 5-10 day turnaround; recommendations may include draft angles, parting line placement, gate location, undercut handling, wall thickness optimization
Quotation and timeline — supplier quotes mold cost, per-part production cost, lead time for mold + first article approval; typical mold timeline 4-8 weeks for P20 production mold, 8-14 weeks for premium tooling
Mold deposit and design approval — typically 30-50% deposit to start mold work; supplier completes mold design with customer approval before manufacturing
Mold manufacture — typical 4-12 weeks depending on tier; complex tooling longer; supplier provides milestone updates
First article inspection — supplier produces 50-200 first-shot parts for customer evaluation; verify dimensional accuracy (CMM measurement), material spec, surface finish, function fit; first article approval (FAA) sign-off before main production
Production order — first batch typical 5,000-100,000 parts; balance payment for mold + production payment
Quality acceptance — incoming inspection per AQL plan (typical 1.0-2.5% AQL); CPK measurement on critical dimensions; supplier provides PPAP documentation for automotive applications
Series production — ongoing per-part orders against forecast; quarterly business review for performance management; mold stored at supplier facility for ongoing production

Frequently asked questions

How does Chinese contract manufacturing quality compare to Western suppliers (Foxconn, Flex, Jabil)?

For mainstream contract manufacturing, premium-tier Chinese suppliers like Kemal Manufacturing deliver products at quality close to Tier-1 EMS at significantly lower cost. The performance parity is achievable because: (1) MANUFACTURING TECHNOLOGY — same equipment (Husky, Engel, Sodick, Mazak, DMG Mori) used across global suppliers; (2) RAW MATERIALS — same global suppliers (BASF, Dow, Covestro, SABIC); (3) PROCESS CONTROL — modern Chinese contract manufacturers have invested in process control matching Tier-1; (4) SKILLED LABOR — China has decades of contract manufacturing experience with skilled workforce. WHERE TIER-1 EMS RETAINS ADVANTAGE: (1) PROPRIETARY HIGH-RELIABILITY processes (advanced PCB assembly, specialty automotive Tier-1 with deep IATF integration); (2) GLOBAL FOOTPRINT for multi-country production; (3) VERTICAL INTEGRATION (Tier-1 EMS like Foxconn handle PCB through final assembly through global logistics); (4) TOP-TIER CUSTOMER MANAGEMENT for fortune-100 tier customers. FOR MAINSTREAM USE (consumer products, mid-tier medical, automotive Tier-2/3, industrial OEM, startup), premium Chinese contract manufacturers deliver fully-equivalent quality at 50-70% of Tier-1 pricing. PROCUREMENT STRATEGY: (1) Mainstream consumer / industrial OEM products → premium Chinese supplier; (2) Highly-regulated medical Class III, premium aerospace, mission-critical automotive → consider Tier-1 for risk management; (3) Volume-balanced approach — primary supplier in China + secondary backup for risk; (4) Quality verification — same incoming inspection rigor regardless of supplier choice. Reputable Chinese suppliers maintain ISO 9001 / ISO 13485 / IATF 16949 certifications and provide complete documentation packages.

How do I choose between CNC machining and injection molding for my parts?

Volume and material choice drive the decision. CNC MACHINING — best for: (1) PROTOTYPE/LOW-VOLUME (1-1,000 parts); no tooling investment; flexible to design changes; (2) METAL PARTS (CNC is the dominant method); (3) HIGH-PRECISION REQUIREMENTS that injection molding can't achieve (tolerance <0.01mm, complex undercuts); (4) SPECIALTY MATERIALS (high-temperature alloys, rare metals); (5) INDIVIDUAL CUSTOMIZATION (unique parts each time). Cost: USD 1-200 per part depending on complexity; no tooling cost. INJECTION MOLDING — best for: (1) HIGH-VOLUME PRODUCTION (1,000+ parts); per-part cost drops dramatically with volume; (2) PLASTIC PARTS (most efficient); (3) COMPLEX GEOMETRIES with consistency (intricate shapes reproduced exactly each time); (4) SECONDARY OPERATIONS REDUCED (parts come out near-final, less post-processing); (5) TIGHT TOLERANCES on plastic parts. Cost: high tooling investment (USD 3,000-150,000) but per-part cost USD 0.05-15.00; per-part cost drops with volume. CROSSOVER POINT: typically 1,000-5,000 plastic parts where injection molding total cost (tool + parts) becomes cheaper than CNC machining the same parts. FOR PROTOTYPING: CNC machining or 3D printing for first 1-100 parts; bridge mold (~USD 3,000-15,000) for 1,000-10,000 part bridge production; production tooling for >10,000 part forecasts. HYBRID APPROACH: many products use CNC for metal parts + injection molding for plastic parts of same product; supplier should support both capabilities.

What's the typical timeline from CAD design to production parts?

Project timeline depends on tooling complexity and verification rigor. WEEK 1-2: DFM review and quotation; supplier engineering reviews design for manufacturability and quotes timeline + price. WEEK 2-3: Customer review of DFM feedback, design refinement if needed, formal order placement with deposit. WEEK 3-7: Mold design and approval (P20 standard timeline); supplier provides 2D mold drawings and 3D mold model for customer approval; design changes captured before manufacturing. WEEK 5-14: Mold manufacturing (varies by tier — P20 typical 4-8 weeks, premium H13 with hot-runner 8-14 weeks); milestone updates from supplier. WEEK 12-15: First Article Inspection (FAA) — first-shot samples sent to customer; CMM measurement, function testing; typical 1-3 weeks for customer review. WEEK 14-20: Mold revisions if needed (typical 1-3 weeks for adjustments); approval to start main production. WEEK 16-22: First production batch typical 5,000-50,000 parts; quality release and shipment. TOTAL FROM DESIGN TO PRODUCTION PARTS: 4-6 months for P20 production mold; 5-8 months for premium tooling. RAPID-OPTION TIMELINES: aluminum prototype mold or bridge mold in 2-4 weeks; CNC machined parts in 7-21 days; soft tooling for 100-500 parts in 4-6 weeks; 3D printing for prototype in 3-10 days. PROJECT MANAGEMENT: experienced suppliers like Kemal Manufacturing provide milestone tracking and proactive communication; customers should track milestones weekly and respond promptly to supplier requests for design clarification or approval. Project delays usually trace to: customer slow response on DFM feedback, design changes mid-mold, or unrealistic quality requirements not caught in initial DFM.

What documentation do I need for medical device contract manufacturing?

Medical device contract manufacturing requires extensive documentation. SUPPLIER QUALIFICATIONS: (1) ISO 13485:2016 certification — quality management for medical devices; (2) FDA establishment registration if shipping to US; (3) MDD/MDR compliance for EU shipments; (4) Specific country registrations for markets like Brazil (ANVISA), China (NMPA), Japan (PMDA). MATERIAL DOCUMENTATION: (1) USP Class VI biocompatibility for materials contacting body; (2) ISO 10993 biocompatibility testing per relevant chapter; (3) DMF (Drug Master File) reference for materials in drug contact; (4) FDA 21 CFR Part 177 compliance for food-contact materials. PROCESS DOCUMENTATION: (1) Validated processes per FDA Process Validation Guidance and ISO 13485 process validation; (2) IQ/OQ/PQ documentation for production equipment; (3) Lot traceability with material certification per lot; (4) Complaint handling and CAPA system. CHANGE CONTROL: (1) Supplier change control system with customer notification of any process or material changes; (2) Change validation documentation. CUSTOMER INSPECTION RIGHTS: (1) Audits of supplier facility (annual minimum); (2) Source inspection access to production; (3) Quality system review. CONTROL OF NONCONFORMING PRODUCT: (1) Quarantine procedures; (2) Disposition documentation; (3) Customer notification of any nonconforming material that may have shipped. RISK MANAGEMENT: (1) Risk assessment per ISO 14971; (2) FMEA for production processes. Reputable Chinese suppliers like Kemal Manufacturing maintain full ISO 13485 systems and provide complete documentation packages for medical device contract manufacturing. Project setup cost is significant (typical 3-6 months for full medical device qualification) but supplier relationships then run profitably for many years.

How do I source qualified Chinese contract manufacturer for confidential / IP-sensitive products?

IP protection is critical for contract manufacturing engagements. STEP 1 — NDA (NON-DISCLOSURE AGREEMENT): execute NDA before sharing any design files; ensure NDA is enforceable in China courts (Chinese law jurisdiction, Chinese language version). STEP 2 — SUPPLIER SELECTION CRITERIA: prefer suppliers with ISO 9001 quality system (implies process discipline), no obvious competitor relationships, strong reputation for IP respect from existing customers. STEP 3 — DESIGN FILE PROTECTION: (1) Share files only after contract execution and deposit payment; (2) Use watermarked / digital-signed files; (3) Limit file access to specific personnel; (4) Track file distribution. STEP 4 — TOOLING OWNERSHIP: customer should own injection molds and CNC fixtures, not supplier; tooling stays at supplier facility but legal ownership protects in case of dispute or relationship break. STEP 5 — TRADE SECRET PROTECTION: (1) Distribute design across multiple suppliers (each sees subset, not full design); (2) Hold proprietary processes outside supplier scope (final assembly or specific calibration done in-house); (3) Trademark and patent registration in China before commercialization. STEP 6 — RELATIONSHIP MANAGEMENT: (1) Long-term supplier relationship — frequent visits, predictable orders, fair pricing; (2) Avoid bait-and-switch suppliers with first-order pricing far below competitors (usually inflate later or copy product); (3) Watch for design appearing in supplier marketing materials or competitor product. STEP 7 — RECOURSE PLANNING: (1) Document all communications; (2) Customer-owned tooling limits supplier leverage; (3) Backup supplier qualification protects against single-source risk; (4) Trade secret protection through professional procedures matters more than legal claims. PRACTICAL REALITY: established Chinese contract manufacturers like Kemal Manufacturing have major Western customers (Apple suppliers, medical device OEMs, automotive Tier-1) that demand strict IP protection — these suppliers maintain rigorous protocols. Smaller / startup-grade suppliers carry higher IP risk; vetting matters.

What's the typical cost structure for plastic injection molding production?

Production cost has three main components: tooling, material, and processing. TOOLING COST (one-time): USD 3,000-150,000 amortized over expected production volume. PER-PART COST = MATERIAL + PROCESSING + MARGIN. MATERIAL COST: depends on plastic type and part weight. ABS at USD 2.50-3.50/kg; for 50g part, material = USD 0.13-0.18 per part. PC at USD 4.50-6.50/kg; for 50g part, material = USD 0.23-0.33. PROCESSING COST: depends on cycle time and machine size. Small machine (50T) at USD 8-15/hour; medium (300T) at USD 15-25/hour; large (1500T) at USD 30-65/hour. Cycle time typical 15-90 seconds per part. For 30-second cycle on 200T machine at USD 18/hour: USD 0.15 per part processing. PRODUCTION OVERHEAD: typically 25-45% markup on direct cost for supplier margin and overhead. TYPICAL CONSUMER PART (50g ABS, 30-second cycle, 200T machine): material USD 0.15 + processing USD 0.15 + overhead USD 0.10 = USD 0.40 per part. ECONOMICS BY VOLUME: at 100,000 parts (USD 40,000 total + USD 8,000 mold = USD 48,000 total / USD 0.48 per part). At 1 million parts (USD 400,000 total + USD 8,000 mold = USD 408,000 total / USD 0.41 per part). Volume drives per-part cost down through (1) Mold amortization across more parts; (2) Better material pricing on bulk orders; (3) Operational efficiency in continuous production; (4) Multi-cavity tooling reduces processing cost per part. SECONDARY OPERATIONS: painting USD 0.15-0.85 per part; pad printing USD 0.05-0.45; assembly USD 0.05-2.50; vary by complexity.

Product range — actual catalogue images

Service portfolio overview

Injection mold construction tiers

Mold tier selection drives part economics over production lifetime

Material selection for plastic injection

Quality certifications and applications

Pricing brackets — typical contract manufacturing

Order workflow — contract manufacturing engagement

Kemal Manufacturing on weisourcing.com

Kemal Manufacturing

Frequently asked questions

Related buyer's guides + inquiry articles

Packaging Machinery Sourcing & Factory Audit

Concrete Brick & Block Making Machines

Paint Additives, Molecular Sieves & TiO2 Pigments