When considering the CNC operations, they have been spread over a wide range, such as turning, milling, drilling, 3D printing, electric discharge machining, laser jet and water jet cutting. A detailed explanation of these mentioned types of CNC operations are presented in this article.Read More
What is CNC Machining
CNC, stands for Computer Numerical Control, applies to the machine control system but erroneously used as a replacement term for NC (Numerical Control). CNC-machining is a fully automatic, subtractive digital manufacturing technology, whereby the computer software drives the machine tool movement.
CNC is a generic term, used to control a wide range of modern machinery ranging from milling, lathe, grinder, laser cutter, router, edm, wirecut etc. CNC machining has a leading edge over conventional machining, as complex parts and ergonomic shapes can be machined with ease. We frequently use CNC Milling machines and Lathe machines to produce accurate and functional parts with excellent physical properties.
The basic process of CNC operation starts from a CAD model. A CAD model, also known as Computer Aided Design, is a digital representation of a physical part. The CAD model is a core of any manufacturing operation, because it represents the true reflection of the finished product. Any flaws in a CAD model will be reflected in the end-product, this rule applies to both subtractive and additive technologies.
Once the CAD model is fully optimised, it is transferred to the manufacturing software known as CAM software. The CAM software (computer-aided manufacturing), translates the CAD file into the numerical data (also known as G-code). It includes the set of instructions, and known as the back-bone of machine tool functionality. All the machine specific parameters such as tool path, speed, feed rate, step-over, rpm etc can be controlled autonomously through the machine coding.
How CNC Milling machining process works:
CNC machining is a form of subtractive manufacturing, means the process starts with a solid block of raw material and extra material is precisely removed by sharp cutters. Machining process is entirely opposite to additive manufacturing, whereby material is added layer by layer.
Much of modern day machining is carried out by computer numerical control (CNC), in which computers are used to control the movement and operation of the mills, lathes, and other cutting machines.
A typical 3-axis CNC Mill consist of a table to hold the work piece that moves in X and Y axes. This workpiece is formed into a finished shape by cutting step by step with a sharp tool, known as a cutter. This cutter is tightly clamped in a spindle which spins at high RPM and moves vertically up and down or in a horizontal direction depends upon the machine configuration. Generally in 3d machining all X, Y and Z axis move simultaneously. For complex 3D parts, 5-axis machining is used where machine head and table can also swivel in real time. All these machine movements are controlled by cutter path which is generated by CAD/CAM software and transferred to the machine controller in the form of numerical data also known as G-code.
CNC Turning (Lathe Machining):
Generally, a Lathe machine is used for machining cylindrical components, also known as turning operation. The major difference between Lathe and Milling machine is, in Lathe machine work-piece is held in a rotating chuck and cutting tool is fixed to the tool post of the machine carriage. The general process of turning involves rotating a part while a single-point cutting tool is moved parallel to the rotation axis for turning the diameter, or perpendicular to the axis, called facing operation.
CNC lathe machines are widely used for mass production of turning components. It is preferred to machine cylindrical parts on a lathe machine to achieve high accuracy and surface finish. Lathe machines can perform multiple operations such as Turning, Boring, Facing, Threading, Drilling, Parting, Grooving, knurling, Reaming, Tapping.
What is ABS Plastic?
ABS (Acrylonitrite Butadine Styrene) is a general purpose rigid thermoplastic with a combination of properties that make it ideal for the wide range of rapid prototyping applications.
ABS Plastic Properties
- High impact resistance
- Good dimensional stability
- Easy to bond/glue
- Good abrasion resistance
- Easy to machine
- Resistance against many chemicals
- Can be electroplated
ABS Plastic Uses
- Automobile parts - such as dashboard parts, instrument panels, housings, shrouds, door trims and handles.
- Electronic components - keyboards, enclosures, printers, monitors.
- Kitchen appliances, vacuum cleaners, refrigerator parts, washing machine and dryer parts, power-tool housings, food processors, toys.
ABS Part Image
What is Polycarbonate (PC)?
PolyCarbonate (PC) is a tough and durable, transparent engineering thermoplastic notable for its high impact resistance, temperature resistance and optical properties.
Polycarbonate (PC) Properties
- High impact resistance
- Excellent strength retention at elevated temperatures
- Great dimensional stability
- Good abrasion resistance
- Low coefficient of thermal expansion
- Good optical clarity
- Good electrical properties
Polycarbonate (PC) Uses
- Automotive headlamp lenses, Safety shields, Casing and housings, Light diffusers, Tractor parts, Drones, Helmets.
- Medical/Healthcare apparatus, Surgical instruments, Sporting goods, Ski equipment, Visors.
- Electrical/Electronic components, Mobile phone housings, Connectors, Insulators, Telecommunication hardware.
- Air conditioners, Hair dryers, Washing machines, Coffee machines, Food processors.
What is Acetal (POM)?
Acetal also known as POM (PolyOxyMethylene) is an engineering thermoplastic often used for precision components that require high stiffness, low friction and excellent dimensional stability.
Acetal (POM) Properties
- Excellent wear resistance
- Good working temperature
- Glossy appearance
- Dimensional stability
- Excellent mechanical properties
- Low moisture absorption
- High tensile strength
- Low coefficient of friction
- High stiffness
- Chemical resistance
Acetal (POM) Uses
- Industrial products: Gears, slides. bearings, bushes, fasteners, guides
- Automotive parts: Fuel pumps, valves, locks, seatbelt parts, clips and knobs
- Irrigation industry: sprinklers, pumps, couplings
- Plumbing industry: Valves, taps, showers, water meters, pump housings
- Medical and Healthcare apparatus
- Conveyor system components
- Jigs and Fixtures
- Lawn mower and tractor parts
Acetal Part Image
What is Acrylic (PMMA)?
Also known as PMMA (PolyMethyl-MetaAcrylate) is an amorphous thermoplastic material with very good optical properties. Acrylic is often used as a glass substitute. Acrylic is hard and stiff, but brittle and notch sensitive.
- Excellent optical clarity
- Good Abrasion Resistance
- Flammable but low smoke emission
- Good Heat Resistance
- Glossy finish
- Excellent environmental stability
- Good Chemical Resistance
- Automotive light & indicator covers
- Prototypes for clear bottles & containers
- Lenses, Shop-fittings, Aircraft glazing
- Lighting fixtures, Lamp shades
- Motorcycle windshields, Camera parts
- Electronic equipments, LED lights
- Medical devices, Incubators, Dental equipments
- Furniture items, Decoration items, Household products
Acrylic part image
What is Nylon?
Nylon is a generic designation for a family of synthetic polymers known generically as PA PolyAmides. Nylons (Polyamides) comprise the largest family of engineering plastics with a very wide range of applications. Nylons are generally Strong, Tough and Wear Resistant.
- Good abrasion resistance
- Good resistance to fuels, oils and solvents
- High Tensile Strength
- High Impact Resistance
- Good electrical insulating properties
- Low coefficient of friction
- High elongation
- Good fatigue resistance
- Excellent wear resistance
- Good sliding properties
- Automotive parts
- Food packaging
- Machinery parts, Jigs & Fixtures
- Consumer and Industrial products
- Sports & Leisure items, Musical instruments
- Fasteners, Gears, Screws, Bearing, Wheels, Bushes, Slides
- Electronic components, Electrical cables, Switchgear, Circuit boards
- Biomedical applications, Medical devices, Medical implants
- Construction industry, Building products, Furniture items
Nylon part image
What is Polypropylene?
PolyPropylene is a semi-opaque thermoplastic widely used in a variety of applications. Polypropylene has good resistance to fatigue. PP offers a combination of outstanding physical, chemical, mechanical, thermal and electrical properties.
- Excellent resistance to fatigue
- High strength to weight ratio, PP is one of the lightest plastic available
- Resists most alkaline and acids
- Low moisture absorption and non-toxic
- Good impact resistance
- Retains stiffness and flex
- Good combination of toughness and flexibility
- PP is highly flammable material
- Excellent resistance to organic solvents
- Good chemical resistance
- High stiffness
- Good resistance to environmental stress cracking
- Appliance housings, Washing machine parts, Kitchen appliances
- Packaging applications; Flexible Packaging & Rigid Packaging
- Medical and Laboratory applications; Diagnostic devices, Petri dishes, Bottles, Trays
- Casings with Living Hinges
- Automotive parts; Interior trims, Dashboard panels, Battery casings, Fender lining, Bumpers, Door trims
- Food Containers, Tanks, Food trays, Pipes, Crates, Pots
- Industrial Applications, Pump Components
- Household Goods, Consumer products, Toys, Luggage, Furniture items like chairs
Polypropylene part image
What is PVC?
Polyvinyl chloride (PVC) is a solid plastic material made from vinyl chloride, it can be made softer and more flexible by the addition of plasticizers. PVC is one of the most commonly used thermoplastic material used in building and construction.
- Excellent strength and toughness
- Good abrasion resistance and toughness
- Good mechanical strength
- Good chemical resistance
- Good tensile strength
- good insulation material, self-extinguishing
- Weather resistant
- Resistant to inorganic chemicals
- Rigid form of PVC is widely used in construction and building industry; Door & window frames, Cladding, Gutters, Decking, Ducts, Vents, Railing
- Plumbing water pipes, Gardening products, Hoses, Sprinkler system, Irrigation products, Drain pipes, Rainwater system
- Automotive parts, Agricultural machinery products
- Packaging industry; Cosmetics, Shampoo, Oil bottles
- Medical devices, Healthcare products
- Electrical distribution boxes, Insulation pipes, Safety Equipment
PVC part image
What is PTFE (Teflon)?
Polytetrafluoroethylene (PTFE) thermoplastic polymer, which is a white solid at room temperature. Teflon is the trademarked brand name for PTFE owned by Chemours, a spin-off company from DuPont.
- Very high melting point
- Extremely low coefficient of friction
- Maintains high strength, toughness and self-lubrication at low temperature
- Low water absorption
- Good resistance to UV light and weathering
- Chemically inert, means most of the solvents and chemicals won't damage Teflon
- Good electrical insulating power
- Automotive parts; Gaskets, Seals, Piston rings, Power steering components, Valves
- Electrical parts, Semiconductor parts, Flexible PCB, Musical instruments
- Engineering parts; Gears, Slides, Bushes, Bearings, Food processing equipment
- Industrial products, Machinery parts, Components for Space industry
- Impellers, Sensor housings, Pumps, Heat exchangers, 3D-printer parts
- Aerospace and Computer applications, Laser printers, Gaming Mouse and Keyboard parts
- Biomedical applications, Medical devices, Prosthetic ligaments
PTFE part image
What is Aluminium?
Aluminium is the most widely used non-ferrous metal. Aluminium is a soft, Durable, Lightweight, Ductile and Malleable metal with appearance ranging from Silvery to Dull Grey, depending on the surface roughness. Aluminium naturally generates a protective oxide coating and is highly corrosion resistant.
- Good electrical conductor
- Excellent corrosion resistance
- Non-magnetic and non-sparking
- Aluminium is 100% recyclable without any loss of its natural qualities
- Aluminium is a good reflector of visible light and heat
- Highly ductile and malleable
- Durable & non-toxic
- Good thermal conductor, the thermal conductivity of aluminium is about three times higher than steel
- Light weight, weighs around one third of steel
- Easy to machine & cast
- Automotive components: Body parts, engine components, grille, panels, motors, hubcaps, powertrain parts, suspension and steering
- Large number of components for marine industry, aircraft, trucks, trains, ships
- Packaging application like beverage cans, foils, bottles, containers,
- Construction industry, Wide range of household items, Fence, Ladders, hinges, latches
- Heat sinks for electronic appliances, consumer electronics, cameras, PC & laptop components, fan blades, ducts
- Architectural & Building industries: Extrusion sections for window and door frames, cladding, hardware items
- Jigs & Fixtures, tooling, moulding inserts, hardware items
Aluminium Part Image
What is Stainless Steel?
Stainless Steel is a generic term for a family of corrosion resistant alloy steels containing at least 10.5% of Chromium. All stainless steels have a high resistance to corrosion. The ease with which it can be steam-cleaned and sterilised, and the absence of the need for surface coatings, have prompted the use of stainless steel in kitchens and food processing plants.
Stainless Steel Properties
- Resistance to corrosion and staining
- Low maintenance, and familiar lustre make stainless steel an ideal material for many applications where both the strength of steel and corrosion resistance are required
- Good performance at both low and high temperatures
- High tensile strength
- Excellent fire resistance
- Stainless steel is 100% recyclable
- All stainless steels have a high resistance to corrosion
- Hygienic with excellent cleanability
- Annealed austenitic stainless steels are usually non-magnetic
Stainless Steel Uses
- The cleanability of stainless steel makes it the first choice in hospitals, kitchens, food and pharmaceutical processing facilities
- Surgical supplies, medical equipment, cookware, cutlery, surgical instruments, washing machine drums, catering equipment, brewing, distilling
- Food processing, street furniture, auto parts, fasteners
- Household appliances, coffee machines, food processors
- Air conditioners, hair dryers, washing machines, electronic items
- Automotive and aerospace applications
- Building and infrastructure
Stainless Steel Image
What is Mild Steel?
Mild Steel is the most common form of steel, widely used in various industries. Mild steel is a form of low-carbon steel comparatively having low amount of carbon contents ranging from 0.05 to 0.25%, making it malleable and ductile. It becomes malleable when heated, and so can be forged.
Mild Steel Properties
- High tensile strength
- Good ductility and weldability
- High impact strength
- Magnetic metal due to its ferrite contents
- Mild Steel is hard, yet malleable, even when cold
- Mild steel can be machined and formed into different shapes easily due to its inherent flexibility
Mild Steel Uses
- Mild Steel is extensively used as structural steel in manufacturing and construction industry due to easy processing and relatively economical than other steels
- Machinery, Ship-building and automobile manufacturing
- Hardware items, fence, fasteners, hinges, appliances
- Pipelines and poles manufacturing due to ease of welding and stability in harsh environment
- Industrial products and tooling components
- Transportation industry
- Automotive products
Mild Steel image
What is Copper?
Copper is one of the few metals that can occur in nature in a directly usable metallic form. Copper is a very durable, soft, malleable and ductile metal with very high thermal and electrical conductivity. It conducts electrical current better than any other metal except silver. Copper is recyclable without any loss of quality, copper's recycling rate is higher than any other engineering metal. Copper is used mostly as a pure metal, but when greater hardness is required, it is put into such alloys as the most well-known copper alloy families are brass (copper-zinc) and bronze (copper-tin)
- Durable and will not rust
- Ability to be recycled multiple times, without any loss in performance, is an important sustainable benefit
- Highest thermal conductivity of any engineering metal
- Highest electrical conductivity of any engineering metal
- High ductility and malleability
- Antimicrobial effect and supports its use in applications where control of contamination benefits
- Electrical equipment: wires, cables, motors
- Plumbing pipes and fittings
- Architectural and building material like roofing, hardware items, down pipes, fascia, gutters
- Industrial machinery, electrodes for spark erosion (EDM) machine, heat exchangers
- Utensils, pans, jewellery items
- Art & craft, decoration items, statues, artwork
What is Brass?
Brass has long been a popular material for decoration for its bright gold-like appearance. The most commonly used colour of brass is bright golden. Brass is an alloy of copper and zinc, in proportions which can be varied to achieve varying mechanical and electrical properties. Brass is commonly used in applications where low friction and corrosion resistance is required. Brass components can often be used without any extra surface protection.
- Good conductor of heat, making it a first choice for heat exchangers (radiators)
- Desirable acoustic properties appropriate for use in musical instruments
- Brass is not ferromagnetic, it can be separated from ferrous scrap with the magnet
- Durable and hygienic, making it suitable for frequently touched surfaces
- Easy to machine and cast
- Corrosion resistant and low friction
- Brass is more malleable than bronze or zinc
- Musical instruments
- Locks and door handles
- Electronic and electrical components
- Plumbing hardware, furniture items
- Valves, taps, heat exchangers
- Gears, fasteners, brackets, screws,
- Home decor, trophies, showpieces, sculptures, vases, artwork, statues
What is Zinc?
Zinc is the world’s fourth most widely consumed metal after iron, aluminium and copper. Zinc is a slightly brittle metal, and zinc has a bluish white surface appearance. It is brittle by nature, but exhibits good malleability and ductility at higher temperatures and easy to machine. Zinc is primarily used in order to galvanise steel because of its useful anti-corrosive properties and ability to bond well to other metals. Zinc metal is employed to form numerous alloys with other metals such as Brass, bronze, nickel silver are common examples.
- Alloys of zinc with base metal as zinc and small amounts of aluminium, copper and magnesium (also known as Zamak) are useful in die casting of automotive, hardware and electrical industries
- The melting and boiling point of zinc is among the lowest of the engineering metals
- Zinc is an environmentally friendly metal due to its infinite recyclability
- Zinc is a fair conductor of electricity and has a relatively low melting point
- Zinc is hard and brittle at ambient temperatures, but becomes malleable between 100 and 150 °C
- Zinc is extensively used to produce die casting components for automotive, hardware and electrical industries
- Architectural and building products like roofing and facade applications
- Zinc oxide is widely used in manufacturing of cosmetics, paints, rubber parts, pharmaceuticals
- Zinc is used as an anode material for batteries
- The semiconductor properties of zinc oxide make it useful in photocopying products
- Zinc coating can be applied to steel components as a protective coating to provide as barrier and sacrificial protection
Zinc part image
CNC Machining offers a wide range of material selection, including plastics and metals. The physical properties of CNC manufactured parts, closely resemble with the mass-produced components, such as injection mouldings or metal castings.
CNC machined parts can hold tighter dimensional tolerances compared to additive manufacturing technologies such as 3D printing. High precision machined components can be directly used for assembly-fitment, without any post-processing work.
CNC machining enhances the capability of producing complex shapes and designs, which are hard to produce by conventional machines. The organic geometries can be machined as efficiently as flat surfaces, thanks to the advanced controllers fitted in CNC machines.
The latest development in CNC machining, provides an ideal solution for small to large orders since it can manufacture hundreds to thousands of functional parts in a short period. CNC machined plastic and metal custom parts can be supplied in as little as 10 days.
An accurate movement of machine tools is controlled by NC programming, makes it possible to deliver precision results repeatedly. An advancement in work-holding devices and tool cutters also help to produce consistent results again and again.
CNC machining can be very efficient and perform as fully autonomous operation, thus reducing the labour cost. Once the digital parameters are uploaded onto the CNC machine controller, it can run by itself with little or no human intervention.
ABS PlasticChrome Plated
Aluminium 6061Clear Anodised
ABS PaintedPainted and Printed
ABS PaintedMatt finish
ABS PaintedMetallic Painted
Polycarbonate (PC)Translucent Finish
Acrylic (PMMA)Tinted in Black
ABSNatural Raw Finish
Aluminium 5083Machine Finish
Acrylic (PMMA)Clear Polished
AluminiumBead Blasted Finish
Stainless SteelMachine Finish
ABS & PCGloss Painted
What is the best CAD file format for CNC machining?
STEP file is our preferred CAD file format for CNC machining, even for 3D printing. Please do not submit STL file for machining, as we can't machine on STL files due to triangular mesh geometry, also it becomes very difficult to modify STL files.We prefer 3D CAD files in one of these formats:
- STP or STEP (.stp or .step)
- IGS or IGES (.igs or .iges)
- PARASOLID (.x_t or .x_b)
Which materials are used in CNC machining?
We have a wide range of materials available as outlined below.For Plastics:
- Polycarbonate (PC)
- Nylon (PA66)
- Polypropylene (PP)
- Acrylic (PMMA)
- Acetal (POM)
- Teflon (PTFE)
- Low or Medium carbon Steel
- Stainless Steel
What is the difference between Milling and Lathe machining?
Milling is a subtractive manufacturing process, whereby the workpiece is clamped on the machine table and a rotary cutter is used to remove an excess material. For manual machining, cutter and machine table movement is controlled manually however in CNC machining these movements are controlled automatically using NC code also known as G-code.Lathe Machining:
Generally Lathe machine is used for machining cylindrical components, that's why it's also known as Turning operation. The major difference between Lathe and Milling machine is, in Lathe machine work-piece is held in a rotating chuck and cutting tool is fixed to the tool post of the machine carriage.
What is the difference between CNC Machining and 3D Printing?
CNC machining is a subtractive manufacturing process; it means the end-product is produced by removing extra material from the work-piece.
CNC machining is one of the most commonly used manufacturing technology to produce end-use products, without sacrificing material properties.
On the other hand, 3D Printing is a form of additive manufacturing; it means material is added layer by layer. 3D printing is leading the way in prototyping industry, especially at the early stage of product development due to quick turnaround and affordability.
- Precision components with tight tolerances
- Functional prototypes
- End-use products
- Low to mid-volume production
- Smooth surface finish
- Reasonable lead time
- Large or bulky parts
- Wide range of material selection
- Quick turnaround
- Complex shapes which are hard to machine
- Economical solution
- Hollow parts or undercut features
- One-off or small quantity orders
What are the limitations of CNC machining?
Setup cost is higher
In CNC machining process, initial setup cost is higher, it's not as simple as printing on 3D printer. Firstly, you need to use CAM program to prepare the machine code (also known as NC code), which is used to control, automate, and monitor the movements of a CNC machine. However, once you have a NC code prepared, it can be used again and again to produce identical parts. Sometimes rigid and purpose built work-holding devices required, depends upon the part geometry.
Hollow parts are hard to machine
Contrary to 3D printing, it's difficult to machine voids or hollow parts. If it's necessary, then parts need to be cut into sections and bonded after machining the internal voids. The undercuts are also challenging to machine.
The machine operator has a significant level of control over the accuracy of a CNC machining project. Careful attention is required from the machine operator to ensure that all the product features are machined to the full extent.
How to improve part design for CNC Machining?
It's challenging to machine complex shapes accurately and effectively. It all starts from product designing stage, if product is designed with fundamental machining concepts in mind, it makes machining process lot smoother and will henceforth improve the product quality and reduce cost. Machining process has its own limitations, so if a part has no undercuts or voids or narrow features, we call it a machining friendly part.You can consider the following points to design machining friendly parts:
- Avoid undercuts or bottlenecks wherever possible, special T-slot cutters are required to machine undercuts or clip features.
- Avoid any lettering or small features which are not necessary for prototyping. For example, engraved (debossed) text or logo is much easier to machine compared to embossed text.
- Sharp internal corners on vertical walls cause slowing down the machining process, so avoid unnecessary sharp or small fillet corners.
- Avoid deep, narrow pockets.
- Avoid thin walled features, ribs, bosses.
- Hollow parts are difficult to machine, if you definitely need hollow features, then in such case part needs to be cut into sections and bonded after machining.
- Unnecessary tight tolerance and finer surface finish on the machined parts can add up to the cost
- Use standard holes and tapping sizes wherever possible
Are you looking to get your parts CNC Machined out of Plastic or Metal?Please feel free to fill up our online quotation form for obligation free quote.
Between the design phase and the marketing phase of a particular product or an equipment, there are several steps that we should follow. One of the key milestones of the product manufacturing process is the selection of the most appropriate process for the production.Read More
Technical Data comparison of various prototyping materials, including Mechanical, Physical, Thermal & Electrical properties compared in an interactive sliding scale. A handy PDF property chart of plastic materials can be downloaded from this page.Read More