CNC Milling Service:
Weldo supports a wide range of metals, plastics, composite and ceramics, delivering custom parts from prototypes to batch production based on your drawings.
- Custom design cnc machined parts
- Sample / Bulk production welcomed
- Tolerances up to ±0.002''
- 95% on time delivery
Online cnc milling process for custom part
We have professional 3-axis, 4-axis, and 5-axis CNC machines. Weldo’s professional CNC milling service can help you present your design in a short time with high precision and high quality.
3-axis cnc milling
For parts with simpler designs, removing excess material in the x, y, and z directions can produce prototypes efficiently and economically.
4-axis cnc milling
The workpiece base has one more rotating plane (a-axis) than the three-axis, which is convenient for milling and drilling on the rotating surface.
5-axis cnc milling
additional rotation plane (C-axis) to control the horizontal and vertical rotation of the workpiece, making the milling process more complex and three-dimensional.
Prototype
Flexibly and quickly produce prototypes to accelerate product assembly, testing, and development.
Small batch and production
ensures consistent material quality and high precision from small batches to mass production
Advantage of CNC milling(mill):
High Precision: Easily handles a wide variety of machining features, achieving micron-level precision.
High Efficiency: Capable of processing parts ranging in size from 0.5 cm to 3000 cm; enhances the efficiency of mass production and minimizes operator errors.
Broad Material Compatibility: Easily processes a diverse range of metals, engineering plastics, and composite materials, offering wide-ranging application possibilities.
WELDO cnc milling solution
CNC Milling Common Materials
We recommend suitable materials based on application environment, design, and budget.Our capabilities cover a wide range of metals and plastics, including aluminum, stainless steel, ABS, POM, and PC.
Metal cnc material type:
Aluminum
It features low density and a hard texture, yet the material itself is relatively pliable. Highly corrosion-resistant, it is widely utilized in the fields of aerospace, biomimetic skeletal structures, and automotive component manufacturing.
Color : Silver.
Types : Aluminum 6061、7075、2024、5052、6063 and MIC-6.
Surface finish : Polishing, Brushing, Sandblasting, Chrome Plating, Anodizing, Electroplating, Powder Coating, Laser Etching.
Delivery time : 1-5 days.
Stainless steel
Corrosion-resistant, smooth, and easy to clean, used in kitchen, medical, construction, and automotive parts.
Color : Silver.
Types : Stainless steel 304/316/201/202/430/444/410/420/440c/2205/2507/17-4ph/17-7ph.
Surface finish : Polishing, Brushing, Sandblasting, Electroplating, Spraying, PVD (Physical Vapor Deposition), Passivation, Pickling, Coloring.
Delivery time : 2-5 days.
Copper
Possesses electrical conductivity, tensile ductility, and antimicrobial properties, primarily used for processing into crafts, decorative items, and medical equipment.
Color :Orange,yellow.
Types : copper H59/H62/Hpb59-1/C36000/HAI77-2/HSN62-1/HPb/HMn/HAl/HSn/HNi.
Surface finish : Passivation, Electroplating, Chemical Plating, Shot Peening, Sandblasting, Chemical Film Treatment, Polishing, Bright Cleaning.
Delivery time : 1-5 days.
Bronze
Bronze is a corrosion-resistant copper alloy with good fluidity and varying color by composition. It’s used for parts like bearings, gears, and marine components.
Color : gold/brown.
Types : Tin bronze, aluminum bronze, beryllium bronze, silicon bronze, manganese bronze.
Surface finish : Sandblasting, polishing, knurling, grinding, passivation, chemical film coating, impregnation coloring, brush/spray coloring, electroplating, anodizing, powder coating, brushing.
Delivery time : 1-5 days.
Steel
Iron-based alloy with Cr, Ni, and Mn, offering adjustable properties via heat treatment. Used for bolts, shafts, gears, cutting tools, and engine components.
Color : Silver .
Types : Steel S20C,S45C,S50C,SK85,SK95,40Cr,4140,4130,H13,D2,W1,A2,D2,M2,SKD11,ASP-23,S136.
Surface finish :Sandblasting, Mirror Finish, PVD Coating, Brushed Finish, Spray Coating, Electroplating.
Delivery time : 1-5 days
Magnesium
Lightweight and possesses low hardness, excellent thermal conductivity, and causes minimal tool wear. Its strength surpasses that of aluminum alloys and steel, and its damping capacity—1.5 times that of aluminum—enables it to effectively absorb vibrations and noise. Suited for use in aerospace and automotive components.
Color : Silver.
Types : Magnesium alloy AZ91D/AM60B/AM50A/AS41B/ZK60/MB8/AZ31/WE43/ZE41/LA141/LZ91.
Surface finish : Chemical conversion coating, anodizing, nickel plating, electroplating, composite coating, spray painting, powder coating, electrophoretic coating.
Delivery time : 1-5 days.
Plastic cnc material type:
ABS
Combining rigidity, toughness, and easy processing, it’s ideal for precision parts under moderate loads, such as electronic housings, automotive air ducts, and trim components.
Color : Beige,black.
Types : General-purpose, flame-retardant, heat-resistant, high-impact-resistant, transparent (MBS), filled modified, alloyed, functionalized ABS.
Surface finish :Spray coating, electroplating, screen printing, laser engraving, hot stamping, vacuum coating, transfer printing, sandblasting.
Delivery time : 1-5 days.
PVC
PVC is a robust, dense material characterized by excellent tensile strength and moderate elongation. Due to its resistance to chemical corrosion and aging, it is an ideal choice for corrosive environments.
Color : White,Beige,black.
Types : Rigid PVC and Flexible PVC.
Surface finish : Painting and plating, polishing, sanding
Delivery time : 1-5 days.
POM
High-strength, low-friction, and dimensionally stable material, ideal for machining. It replaces metal in wear parts like gears and bearings.
Color : white,black,blue,yellow,etc.
Types : POM-H, POM-C.
Surface finish : Polishing, sandblasting, chemical polishing, laser polishing, anodizing/painting.
Delivery time : 1-5 days.
PTFE
PTFE offers ultra-low friction, strong chemical resistance, and excellent insulation, ideal for seals, gaskets, and bushings.
Color : White, natural, black, filled or custom-colored.
Types : Virgin PTFE，Glass-filled PTFE，Carbon-filled PTFE，Bronze-filled PTFE，Modified PTFE
Surface finish : Machining finish, polishing, texturing, coating, engraving, anti-static treatment.
Delivery time : 1-5 days.
PMMA
92% light transmittance “plastic crystal” for lenses and light guides—lighter than glass, easy to machine, and ideal for display covers and phone frames.
Color : clear,white,black,colored.
Types : General-purpose / Impact-resistant / Heat-resistant / Pearlescent.
Surface finish : Polishing, enhanced coating, sandblasting for texture, printing for coloring, anti-scratch and anti-fingerprint treatments.
Delivery time : 1-5 days.
PC
High-performance thermoplastic with excellent toughness, rigidity, and insulation—lightweight and ideal for CNC-machined electronic components.
Color : white or black.
Types : General Machinable/Flame Retardant/Reinforced/Blended PC.
Surface finish : Polishing, Hardening, Spraying, Laser Engraving, Electroplating, Hot Stamping.
Delivery time : 1-5 days.
FR4
FR4 is a glass-fiber epoxy laminate with high strength, excellent insulation, and stable performance. It’s widely used for structural and insulating parts like spacers, brackets, and mounting plates.
Color : Yellow, green, black, white, natural
Types : Standard FR4 / High-Tg FR4 / Halogen-free FR4
Surface finish : Machining finish, polishing, sandblasting, coating, painting, laser marking
Delivery time : 1–5 days
PA
PA (Nylon) offers 62 to 85 MPa tensile strength, low friction, and heat resistance, ideal for gears and bearings in automotive, electronics, and machinery.
Color : Colored.
Types : PA6, PA66, PA6T, PA9T.
Surface finish :Mechanical grinding, acid/alkali etching, hydrolysis technology, coating.
Delivery time : 1-5 days.
PE
PE is a low-melting thermoplastic requiring temperature control during machining to avoid adhesion. It offers low friction, chemical resistance, and is widely used in sliding parts, containers, and toys.
Color : black,white,colored.
Types : LDPE, HDPE, UHMWPE, PEX, PEX-A, PEX-B.
Surface finish :Polishing, sandblasting, coating, etching.
Delivery time : 1-5 days.
PEEK
PEEK is a high-strength, high-temperature engineering plastic with low friction and excellent chemical resistance. It is widely used in aerospace components, high-heat parts, and medical devices.
Color : Beige,black.
Types : CF-PEEK, GF-PEEK, PEEK with carbon black/ceramic/PTFE/graphite fillers.
Surface finish :Sandblasting, polishing, metal coating, polymer coating.
Delivery time : 1-5 days.
PP
PP is a semi-crystalline thermoplastic with good flow, requiring temperature control during CNC machining. It’s widely used for containers, connectors, and structural parts.
Color : black,white,colored.
Types : PP-H, PP-B, PP-R, HIPP.
Surface finish :Polishing, Sandblasting, Coating.
Delivery time : 1-5 days.
HDPE
HDPE is a durable, non-toxic thermoplastic with strong impact resistance and stability, used for valves, pump parts, gears, bearings, and core materials.
Color : black,white.
Types : HI-HDPE, UV-HDPE, UHMWPE, Carbon Black-Filled HDPE.
Surface finish :Polishing, Sandblasting, Coating.
Delivery time : 1-5 days.
HIPS
HIPS is a rubber-modified thermoplastic with high impact resistance, easy processing, and low cost. It is widely used in housings, packaging, automotive interiors, and lightweight structural applications.
Color : black.
Types : Impact-resistant HIPS, Brominated flame-retardant HIPS, Glass-fiber reinforced HIPS.
Surface finish :Polishing ，Sandblasting ，Coating.
Delivery time : 1-5 days.
Surface finish for CNC milling parts
Over the past 15 years, we have selected and briefly outlined more than 10 surface finished for various precision machined parts.
Machined finish
The prototype processed by the machine tool retains traces of tool machining.
Anodizing
Improves metal corrosion and wear resistance can be colored and protective coatings.
Polish
Improves surface smoothness and appearance for metals, ceramics, plastics, and PMMA.
Sand blasting
Uses high-pressure abrasives to create a clean, rough, matte surface finish.
Brushed finish
Adds textured patterns to metal surfaces, improving aesthetics.
Powder coating
Uses electrostatic application and heat curing to form a dense layer, improving corrosion resistance on parts.
Electroplating finish
Deposits a metal layer to improve corrosion and wear resistance.
Black oxidize
Forms a low-cost, anti-reflective coating on metal surfaces via simple chemical oxidation.
Alodine
Forms a corrosion-resistant coating via chemical conversion, improving adhesion and conductivity.
Heat treatment
Modifies metal microstructure to improve hardness, strength, toughness, and wear resistance.
Tolerance of cnc milling service
We ensures CNC milling accuracy through strict inspection and reprocessing, meeting ISO2768-m (metal) and ISO2768-c (plastic) standards for high-quality parts.
| Item | 3-Axis Milling | 4-Axis Milling | 5-Axis Milling |
|---|---|---|---|
| Min part size | 2000 mm × 1000 mm × 1000 mm | 1500 mm × 1000 mm × 800 mm | 1500 mm × 1000 mm × 1000 mm |
| Max part size | 5 mm × 5 mm × 5 mm | 5 mm × 5 mm × 5 mm | 5 mm × 5 mm × 5 mm |
| General tolerance | ±0.1 mm | ±0.1 mm | ±0.05 mm |
| Lead time | 1–3 days | 1–3 days | 1–3 days |
CNC milling design guideline
| Item | Design / Machining Guidelines |
|---|---|
| INTERNAL DIAMETER | The internal machining radius should be at least 1/3 of the workpiece cavity depth to avoid “tool chattering”. |
| THREADS AND THREADED HOLES | • The effective depth of the thread should be at least 1.5 to 2 times the nominal diameter• For precision fits or high-load applications, the depth should be 3 to 5 times the nominal diameter• The total depth of the threaded hole (including the ineffective depth) should be 2 to 3 thread pitches longer than the effective depth |
| MINIMUM WALL THICKNESS | • Metal CNC machining: 0.5 – 0.8 mm• Plastic CNC machining: 1.5 mm• Small wall thicknesses can increase wear, tear, and machining time costs |
| SIZE TEST | • CNC milling part: Minimum width of 0.5 mm and depth of 0.1 mm• The workpiece can be CNC routed or laser engraved according to customer needs |
| HOLES | • The recommended hole depth is 3–4 times its diameter• For example, using a 1 mm diameter tool, the recommended hole depth is no more than 4 mm |
CNC Milling Process Steps & Working Principle
Programmers convert 3D designs into G-code instructions to control tool parameters and motion paths, removing excess material.
Step 1: Design and Programming
Create models, generate toolpaths, and verify the G-code to ensure correct machining.
Step 2: Workpiece Setup
Mount and securely clamp the workpiece, prepare tools, and calibrate coordinates to ensure an accurate starting point.
Step 3: Automated Machining
The CNC system drives the machine, spindle, and cooling system to operate according to the programmed instructions.
Step 4: Inspection and Recording
Inspect and record part features, and rework or scrap any non-conforming products.
Application of CNC milling
Aerospace:
Machines titanium and magnesium parts like turbine blades and engine components, meeting high strength and precision demands.
Automotive Manufacturing:
Produces engine blocks, transmission housings, and EV battery frames using cast iron and aluminum alloys.
Mold & Die Industry:
Manufactures injection molds and dies, ensuring high accuracy and consistent batch production.
Electronics & 3C Industry:
Processes phone frames, heat sinks, and micro-cavities with precision up to 0.01 mm.
Medical Devices:
Produces artificial joints, surgical tools, and medical housings to strict standards.
CNC milling FAQ
What are the minimum hole diameter and wall thickness achievable with cNc milling?
Typical minimum hole diameters are approximately 0.5mm for metals and 0.3mm for plastics. Minimum wall thicknesses reach 0.5mm for metals and around 1.5mm for plastics, though these values depend on material hardness, tool precision, and machine rigidity.
What distinguishes CNC milling from 3D printing?
CNC milling employs “subtractive manufacturing” (material removal), ideal for high-precision parts in metals and rigid plastics. 3D printing uses “additive manufacturing,” suited for complex, irregular structures, though typically offering lower precision and material strength than milling.
What are the main advantages of 4-axis and 5-axis CNC milling?
Compared to 3-axis (X/Y/Z), 4-axis (+rotary axis) enables machining of inclined side structures on workpieces. 5-axis (dual rotary axes) achieves one-time complete machining of complex surfaces (e.g., impellers, mold cavities), reducing setup frequency and errors.
What files are required before CNC milling?
Provide the part’s 3D model (e.g., STL, STEP format) or 2D engineering drawings specifying dimensional tolerances, material type, and surface roughness requirements. CAM software generates machining code based on these specifications.
Which materials are unsuitable for CNC milling?
Ultra-soft materials (e.g., rubber), highly elastic materials (e.g., silicone), and brittle materials (e.g., certain ceramics) present significant machining challenges. They often result in surface roughness or tool damage and are better suited for alternative processes.
