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CNC Pocket Milling Service
Are you looking for a way to make perfect cavities in your parts? CNC pocket milling is the answer! At Istar Machining, we’re experts at making closed-boundary milling that removes material to exact depths. This guide will show you everything about pocket milling and how our services can help your projects.
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20+ Years
Istar Machining's years in the industry
300,000 square feet
The size of Istar Machining's factory
856 CNC machines
Our CNC equipment count
2000+ skilled workers
Istar's number of skilled machinists/operators
What Is CNC Pocket Milling?
CNC pocket milling makes hollow areas or cavities in a part without cutting all the way through. Think about the space where a screw head sits flush with a surface – that’s a pocket!
Pocket milling uses special tools and movements to create these spaces with exact:
- Depths
- Shapes
- Surface finishes
How Our CNC Pocket Milling Works
Our process follows these simple steps:
- You send us your design file (like DWG or STEP)
- We create special toolpaths for your pocket
- We use our Haas UMC-750 machine to cut your pocket
- We check everything with our measuring tools
- You get a perfect part!
Cool Things We Can Do With Pocket Milling
What We Make | How We Use It | Why It’s Great |
Flush fasteners | Aircraft and car parts | Screws sit perfectly flat with the surface |
Mold cavities | Plastic injection molds | Makes spaces for plastic to flow into |
Structural pockets | Lightweight parts | Removes weight while keeping strength |
Pressnut spaces | Assembly points | Creates perfect spots for threaded inserts |
Battery trays | Electronic devices | Makes spaces that hold batteries perfectly |
Optical components | Cameras and devices | Super smooth finishes for sensitive parts |
Our Amazing Tools and Methods
We use high-feed carbide end mills from top brands like Sandvik to cut material faster and better. Our special methods include:
- Peck milling cyclesthat safely remove chips from deep pockets
- Trochoidal toolpathsthat make mirror-like finishes (as smooth as 32 microinches!)
- Dynamic millingthat makes tools last 40% longer
- Depth controlaccurate to ±0.005″ (thinner than a human hair!)
Materials and Their Best Uses
Different materials offer unique advantages for CNC pocket milling. Here’s a look at what we commonly work with:
Metals
Aluminum
Stainless Steel
Mild Steel
Alloy Steel
Titanium
Brass
Copper
Magnesium
Aluminum
Aluminum (Common Grades: 6061, 7075, 5052, 2024)
Lightweight, corrosion-resistant, has excellent thermal and electrical conductivity, and is very machinable, making it ideal for pocket milling.
Good for:
- Housings and enclosures
- Jigs, fixtures, and tooling
- Automotive and aerospace components
- Heat sinks and thermal management parts
- Manifolds and fluid handling blocks
- High-speed prototypes
Why customers love it:
“It provides an outstanding balance of strength, weight, machinability, and cost-effectiveness, making it versatile for countless prototyping and production applications.”
Stainless Steel
Stainless Steel (Common Grades: 303, 304, 316, 17-4 PH)
Offers excellent corrosion resistance, high strength, and durability. Pocket milling requires appropriate speeds and feeds due to work hardening.
Good for:
- Medical devices and surgical instruments
- Food processing equipment
- Marine hardware
- Chemical processing components
- Components requiring high strength and corrosion resistance
Why customers love it:
“Its durability and resistance to corrosion and heat make it perfect for demanding environments where longevity and hygiene are critical.”
Mild Steel
Mild Steel (Common Grades: 1018, A36)
A cost-effective, versatile ferrous metal with good machinability and strength. Prone to rust if not finished or coated.
Good for:
- Structural components
- Machine parts and frames
- Jigs and fixtures
- General fabrication
- Prototyping where cost is a major factor
Why customers love it:
“Great value for general-purpose applications requiring good strength and ease of fabrication, easily weldable and machinable.”
Alloy Steel
Alloy Steel (Common Grades: 4140, 4340)
Steels alloyed with elements like chromium, molybdenum, or nickel to enhance properties like hardness, toughness, and wear resistance. Machinability varies by grade and heat treatment.
Good for:
- Gears, shafts, and axles
- Tooling and molds
- High-stress mechanical components
- Automotive and aerospace parts
- Components requiring high strength and toughness
Why customers love it:
“Provides superior strength, hardness, and durability compared to mild steel, suitable for high-performance and demanding applications.”
Titanium
Titanium (Common Grades: Grade 2, Grade 5/Ti 6Al-4V)
High strength-to-weight ratio, excellent corrosion resistance, and biocompatible. More challenging to machine due to low thermal conductivity and chemical reactivity.
Good for:
- Aerospace structural components
- Medical implants and devices
- High-performance automotive parts
- Marine applications
- Chemical processing equipment
Why customers love it:
“Unmatched strength-to-weight ratio and superb corrosion resistance make it ideal for critical applications where performance and low weight are paramount.”
Brass
Brass (Common Grade: C360)
An alloy of copper and zinc, known for excellent machinability, good corrosion resistance, electrical conductivity, and aesthetic appeal.
Good for:
- Plumbing fittings and valves
- Electrical connectors and terminals
- Musical instrument parts
- Decorative hardware
- Low-friction applications (bushings, bearings)
Why customers love it:
“Extremely easy to machine, producing excellent surface finishes. Offers good corrosion resistance and a desirable appearance at a reasonable cost.”
Copper
Copper (Common Grade: C101, C110)
Valued primarily for its exceptional electrical and thermal conductivity. Relatively soft and can be ‘gummy’ to machine, requiring sharp tooling.
Good for:
- Heat sinks and heat exchangers
- Electrical contacts, wiring, and busbars
- Plumbing components
- Architectural elements
Why customers love it:
“Its superior conductivity is essential for thermal and electrical management applications where efficient energy transfer is key.”
Magnesium
Magnesium (Common Alloys: AZ31, AZ91)
The lightest structural metal, offering a good strength-to-weight ratio and excellent machinability. Requires careful handling due to flammability of fine chips/dust.
Good for:
- Ultra-lightweight aerospace and automotive parts
- Power tool housings
- Electronic device casings (laptops, cameras)
- Applications where weight saving is critical
Why customers love it:
“Offers significant weight reduction possibilities compared to aluminum, while still being relatively strong and very easy to machine (with precautions).”
Plastics
ABS
Nylon (PA)
Polycarbonate (PC)
Acetal (POM / Delrin®)
PEEK
Acrylic (PMMA)
HDPE / UHMW
ABS
ABS (Acrylonitrile Butadiene Styrene)
A common thermoplastic known for its toughness, impact resistance, and ease of machining. Cost-effective choice for many applications.
Good for:
- Functional prototypes
- Enclosures and housings for electronics
- Consumer product components
- Automotive interior parts
- Jigs and fixtures
Why customers love it:
“A reliable workhorse plastic that’s easy to machine, reasonably strong, impact resistant, and affordable for prototyping and production.”
Nylon (PA)
Nylon (PA) (Common Grades: Nylon 6, Nylon 6/6, Glass-Filled variants)
A strong, tough engineering thermoplastic with excellent wear resistance, low friction properties, and good chemical resistance. Can absorb moisture, affecting dimensional stability.
Good for:
- Gears, bearings, and bushings
- Wear pads and guides
- Rollers and wheels
- Structural components
- High-impact parts
Why customers love it:
“Its exceptional wear resistance and toughness make it ideal for moving parts and applications requiring durability and low friction.”
Polycarbonate (PC)
Polycarbonate (PC)
A very durable, transparent thermoplastic with outstanding impact strength, good temperature resistance, and dimensional stability.
Good for:
- Machine guards and safety shields
- Optical lenses and light pipes
- Clear manifolds and housings
- High-impact prototypes
- Medical device components
Why customers love it:
“Incredibly tough and shatter-resistant, perfect for applications needing transparency combined with high impact strength.”
Acetal (POM / Delrin®)
Acetal (POM / Delrin®)
An engineering thermoplastic known for its high stiffness, excellent machinability, low friction, wear resistance, and outstanding dimensional stability, especially in wet environments.
Good for:
- Precision gears, bearings, and bushings
- High-performance rollers and sliders
- Electrical insulators
- Fuel system components
- Parts requiring tight tolerances
Why customers love it:
“Machines beautifully to tight tolerances and smooth finishes. Its stiffness, low friction, and stability make it a go-to for precision mechanical parts.”
PEEK
PEEK (Polyether Ether Ketone)
A high-performance engineering thermoplastic offering excellent mechanical strength, stiffness, high temperature resistance, chemical resistance, and wear resistance. Biocompatible grades available.
Good for:
- Aerospace components
- Medical implants and instruments
- Semiconductor handling parts
- Bearings and seals in harsh environments
- High-temperature electrical connectors
Why customers love it:
“Top-tier performance across the board – temperature, chemicals, mechanical stress. Ideal for the most demanding applications where other plastics fail.”
Acrylic (PMMA)
Acrylic (PMMA)
A rigid, transparent thermoplastic with excellent optical clarity and UV resistance. More brittle than Polycarbonate but easier to polish to a high gloss.
Good for:
- Displays and signage
- Light guides and lenses
- Transparent housings and enclosures
- Architectural models
- Decorative items
Why customers love it:
“Offers exceptional clarity, similar to glass, but is much easier to machine and fabricate. Great for visual prototypes and optical applications.”
HDPE / UHMW
HDPE / UHMW (High-Density Polyethylene / Ultra-High Molecular Weight Polyethylene)
HDPE is cost-effective, chemical resistant, and impact resistant. UHMW offers extremely high abrasion resistance and low friction, but can be harder to machine cleanly.
Good for:
- (HDPE) Cutting boards, chemical tanks, low-load structural parts
- (UHMW) Wear strips, chain guides, chute liners, low-friction bearings
- Food processing equipment components
- Marine construction (bumpers, etc.)
Why customers love it:
“(HDPE) Cost-effective solution for chemical resistance and general toughness. (UHMW) Unbeatable wear resistance for sliding applications.”
Other Materials
Composites (G-10/FR-4)
Wood / Engineered Wood
Machinable Foam
Composites (G-10/FR-4)
Composites (G-10/FR-4, Carbon Fiber)
Materials like glass-reinforced epoxy (G-10/FR-4) or Carbon Fiber offer high strength-to-weight ratios and stiffness. Machining creates abrasive dust and requires specialized tooling and procedures.
Good for:
- (G-10/FR-4) Electrical insulators, terminal boards, jigs, structural components
- (Carbon Fiber) Aerospace parts, automotive panels, high-performance sporting goods, robotic arms
Why customers love it:
“Provides exceptional stiffness and strength relative to weight (especially Carbon Fiber) or excellent electrical insulation and stability (G-10/FR-4).”
Note: Machining composites requires specific expertise and equipment due to abrasiveness and dust generation.
Wood / Engineered Wood
Wood / Engineered Wood (Hardwoods, Softwoods, Plywood, MDF)
Natural woods and engineered wood products can be pocket milled. Properties vary greatly by type. Suitable for specific applications like jigs, molds, or decorative elements.
Good for:
- Jigs, fixtures, and shop aids
- Pattern making and molds (low temp)
- Architectural models
- Decorative carvings and inlays
- Prototyping
Why customers love it:
“Readily available and relatively easy to machine for creating custom jigs, patterns, or aesthetic components where metal or plastic isn’t required.”
Machinable Foam
Machinable Foam / Tooling Board (Polyurethane, Epoxy based)
Available in various densities, these materials are very easy and fast to machine. Primarily used for non-functional models and patterns.
Good for:
- Concept models and appearance prototypes
- Patterns for casting or vacuum forming
- Low-temperature molds
- Ergonomic studies
- Checking CNC toolpaths before machining expensive materials
Why customers love it:
“Allows for incredibly fast machining, perfect for quickly creating physical models, verifying designs, and making patterns at low cost.”
Pocket Milling Parts Produced by Istar Machining
Why Our Pocket Milling Is Better
Super accurate depths
We use special probes to ensure your pockets are exactly the right depth
Perfect surface finish
Our techniques create smooth surfaces that need no extra work
Complex shapes
We can make pockets with angled walls or curved bottoms
Fast turnaround
We can finish prototype pockets in just 48 hours!
Custom options
Need special corner radiuses or floor patterns? No problem!
Real-World Uses for CNC Pocket Milling
Pocket milling is perfect for many industries. Here’s where we use it most:
Aerospace
Airplane parts need to be light but strong. We make structural pockets that remove extra material while keeping strength. These parts must meet strict Boeing standards for safety.
Medical Devices
Medical parts need precise cavities for components. Our precision medical machining creates perfect fits for things like batteries or sensors.
Consumer Electronics
Your phone or laptop has many tiny pockets inside for parts to fit perfectly. We can make these with tolerances as small as 0.0015"!
Automotive Parts
Cars need strong, lightweight parts. Our aluminum CNC milling creates perfect pockets for parts that save weight and fuel.
Send Us Your Design
Upload your CAD files (like STEP or IGES format)
Get a Quick Quote
We'll tell you the price and timeline within 1 hour
We Make Your Parts
Our skilled machinists program the CNC machines
Quality Check
Every part is inspected before shipping
Safe Delivery
Your parts arrive on time, ready to use
Get Started With CNC Pocket Milling Today
Ready to make your parts better with perfect pockets? Our team at Istar Machining is ready to help. As a top 5 CNC machining factory in China, we focus on high-precision, custom work that meets your exact needs.
Frequently Asked Question
Yes! With our 5-axis machining, we can create pockets with angles, curves, and undercuts that normal machines can’t make.
We can make pockets up to 4 inches (100mm) deep with special tools that reach down while staying accurate.
Just add a note saying “Depth: X.XX” in your design file, or we can help you figure out the right depth.
For aluminum, we use 3-flute carbide end mills with special coatings that cut smooth and fast.
We can make pocket floors with a mirror-like 32 microinch finish – smooth enough for optical components!
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