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One of the most cost effective ways of making precision components is small batch CNC machining. This presents faster turnaround times and flexibility for design changes compared to mass production. In this blog post we are going to cover its different types, advantages and how it’s used in various sectors.
What is Small-Batch CNC Machining?
Simply put, small batch CNC machining procedures involve using machines, controlled by computers, to create small batches of parts. It has unusually short turnaround times, outstanding precision and is easily adaptable to design changes. The method is very good at producing complicated, custom components with strict tolerances.
Types of Small-Batch CNC Machining
CNC Milling
CNC milling refers to a process, where a fixed workpiece is shaped using a rotating cutting tool. The machine travels in multiple axes to generate precise (+/-0.01 mm) complex shapes. This flexible process is excellent for making slots and flat surfaces on small batch components in many industries.
CNC Turning
CNC turning is the process of making cylindrical parts using computer guided lathes. The static cutting tools remove material from the workpiece as the workpiece rotates to reach tight tolerances down to ±0.01 mm. It’s great at making symmetrical components such as bolts, shafts and custom cylindrical components with outstanding surface finishes.
Wire EDM Machining
In wire EDM the conductive material is cut using a thin electrically charged wire (usually 0.004″ to .012″ diameter) by controlled electrical discharges. This method is common in small batch CNC machining when parts require detailed dimensions and narrow tolerances. Due to minimum material waste, this process is suitable for parts like thin walls, delicate contours or fine holes.
CNC Drilling
In CNC drilling computer controlled machines drill accurate holes in workpieces. The process works well for small batch CNC machining because it allows quick creation of holes with different sizes and depths. CNC drilling is versatile for industries that require high precision components including aerospace and electronics.
Surface Grinding
Surface grinding is the process that uses a rotating abrasive wheel to remove controlled amount of material from a work piece, to produce an ultra-precise flat surface. It produces smooth surfaced, close dimensioned parts like metal plates, precision jigs and tool parts in small-batch production.
Sinker EDM Machining
Sinker EDM uses electrical discharges between a workpiece and a shaped electrode for making complicated three dimensional (3D) cavities. It’s used to make complex cavities, like pockets or grooves, and complicated features such as tapered holes or sharp enclosed corners. In particular this method is excellent for tool steels, exotic alloys or hardened steels such as Inconel and titanium.
3 Axis, 4 Axis, and 5 Axis CNC Machining
The complexity and precision of multi axis machining vary. 3 axis uses three linear axes, 4 axis adds a rotational axis and 5 axis has two additional rotational axes for machining intricate shapes and undercuts in one setup. 4 axis and 5 axis machining cuts down on setup times in small batch manufacturing.
Materials Most Used in Small-Batch CNC Machining
Stainless steel
It is an outstanding corrosion resistant metal and has great tensile strength as well. When making parts that need to function in harsh conditions, CNC machining operators often pick stainless steel.
Brass
Brass is the best material to be used in small batch CNC machining because of its high thermal conductivity of 115 W/m-k and outstanding machinability.
Aluminum
For small batch CNC machining, aluminum alloys are broadly used due to their good resistance against corrosion, machinability and good strength-to-weight ratio.
Mild steel
Mild steel, also known as low carbon steel (0.05–0.25%), is a material that has good ductility, weldability and machinability. In different manufacturing processes, it is a cost effective material and has good strength to weight ratio.
Tool steel
Unlike mild steel, tool steel is very hard, wear resistant and can be heated to high temperatures. It is used in small batch machining because of its ability to hold performance and form in high temperature and stress conditions.
Alloy steel
The alloy steel consists of nickel, molybdenum and chromium to give the alloy its improved properties. It exhibits tensile strengths up to 655 MPa and impressive wear resistance, and excel in high stress operations.
PEEK
Due to PEEK’s high thermal stability (up to 260°C) and strength to weight ratio, PEEK is suitable for small batch CNC machining. This material is used to produce prototype automotive parts and custom aircraft bearings.
Nylon
Nylon has excellent wear resistance, and high tensile strength (up to 12,000 psi). It has dimensional stability over a temperature range from -40°C to 100°C. The low friction coefficient and self-lubricating properties of nylon make it a good material for high wear components.
POM
Polyoxymethylene (POM) is plastic with outstanding wear resistance and dimensional stability. It is a high stiffness, self-lubricating material suitable for small batch precision components.
PTFE (Teflon)
PTFE has a very low friction coefficient (0.05–0.10) and excellent chemical resistance. Because of its ability to operate in harsh environments and its non-stick properties, PTFE is valuable in small batch manufacturing.
ABS
This plastic is versatile and has modulus of elasticity of 2600 MPa and tensile strength of approximately 40 MPa. ABS is used for many electronics enclosures and consumer products because of its mechanical strength.
Polycarbonate (PC)
Polycarbonate is well known for its clarity (refractive index 1.548) and unparalleled impact resistance (250 times stronger than glass). Due to its high heat resistance to 140°C and dimensional stability, it is well suited for precision small batch components.
HDPE
HDPE has a great strength-to-weight ratio, as well as chemical resistance and tensile strength of 38 MPa. Most of the time, is used in small batch production of special chemical containers and medical parts.
Benefits of Small Batch CNC Machining
- In small batch CNC machining, design changes and material switches are possible with no expensive retooling. This allows companies to easily and quickly respond to market needs, create custom parts with little set up and try out new designs.
- Small batch CNC machining removes costly tooling costs that are related with mass production. It provides cheaper manufacturing for small-scale or brief productions without sacrificing precision or quality.
- Small Batch CNC machining uses materials efficiently by controlled batch sizes and smart programming; this helps create less waste during manufacturing.
- Small batch CNC machining speeds up production cycles and significantly lessens the lead times for finished parts.
- Small batch CNC machining is particularly good at making custom parts with detailed part features and complicated geometry. This flexibility is very valuable for industries needing small numbers of parts with special shapes, materials and specifications.
- CNC machining is capable of outstanding precision with tolerance of +/– 0.001 mm for small runs. The machine provides the same quality every time throughout the production cycle.
Small Batch CNC Machining Applications
Aerospace Industry
For aerospace manufacturing, small batch CNC machining produces components with exceptional precision of ±0.001 mm. This produces critical parts such as parts of landing gear, oxygen generation setups and turbine blades which must meet specific industry requirements.
Robotics
Small batch CNC machining is essential for the robotics sector to produce precise components. When producing custom jigs, joints and robotic end effectors, the system achieves tolerances as high as ±0.05 mm. Because of these tight specifications, the robot will operate and move with accuracy and smoothness.
Low Scale Production Runs
Small batch CNC machining is perfect for market testing because of its cost effective production of 10-1000 units. It allows design flexibility between runs, with little to no associated risk to inventory.
Customized Products
From customizable prosthetics to bespoke automotive parts and consumer goods, small batch CNC machining is really good at making specialized parts.
Automotive Industry
Small batch CNC machining is used by automobile manufacturers to create prototypes, gears and engine parts. The process is able to achieve tolerances of ±0.0001 inches which supports rapid design iterations for custom components and performance parts.
Electronics Industry
The electronics sector uses small batch CNC machining to create circuit board enclosures, semiconductor parts and heat sinks. This enables engineers to prototype connectors and intricate electronic housing very quickly.
Medical Devices
Small batch CNC machining can achieve 50 micron tolerances, which helps the medical field. Such precision allows the production of biocompatible components, including housing for diagnostic equipment, surgical tools and customized implants.
Rapid Prototyping
The quick design iterations make small batch CNC machining perfect for prototyping. This method is used by most of the medical companies to test new surgical tools. It’s also used by car manufacturers to verify component designs before they start mass production.
Challenges Associated with Small Batch Machining
- In small batch production runs of 10 to 1000 parts, the cost per unit increases dramatically. It’s because each item covers a greater share of fixed costs such as programming, tooling and setup, compared to mass production.
- When working in small batch sizes, quality control becomes very important. All components must keep within strict tolerances of ± 0.001 inches.
- In small batch manufacturing, effective scheduling is of great importance. Late material delivery affects production schedules as parts with complex designs require multiple machining steps and extra setup time.
- Each new batch necessitates its own setup of machine and tooling. The success lies heavily on having skilled operators that know how to pick and use the right tool for the right job.
Best Practices for Small Batch CNC Machining
Quality Control Measures
For dimensional accuracy, you should incorporate real time monitoring systems with coordinate measuring machines (CMM). In addition to these things, you must apply first article inspection (FAI) processes and statistical process control (SPC). Together, this combination of automated probing systems and final human inspections will assure consistency in small batch quality.
Advance Software for Planning and Simulation
Today’s CAD/CAM software includes extremely powerful geometric and physical simulation capabilities. They can assist you in determining prospective collisions and also confirm the toolpaths before they come into production. This advanced planning results in more precise and faster production times for small batch machining.
Tooling and Fixture Design
You need to implement modular fixtures and quick change tooling systems to reduce setup times from batch to batch. And to keep tolerances of ±0.0001 inch, your fixtures require precise locators and clamps.
DFM principles (Design for Manufacturability)
DFM enables you to optimize your product design based on manufacturing capabilities at the early design phase. Teaches you how to choose the proper materials, keep part geometries easy, and make use of standardized features. In small batch CNC machining, these steps lower complexity and keep production costs down.
Conclusion
In short small-batch CNC machining is perfect for prototypes and custom parts. It gives best quality products, fast turnaround times and also makes low volume production cheaper and practical.
If you need any kind of small batch CNC machining services -milling, turning, grinding, etc- then RICHCONN is your best option. You can contact us any time.
FAQs
Is small batch CNC machining capable of handling complicated designs?
Yes CNC machines can certainly fabricate intricate geometries and even complex features with multi axis capabilities. Besides that the latest CAD/CAM software offers accurate tool path optimization for difficult designs while keeping tight tolerances.
How does small batch CNC machining ensure quality control?
Small batch CNC machining utilizes statistical process control, and automated inspection systems to assure constant quality. Also, in-process checks are used to maintain exact precision in the production process.
How Is Small Batch CNC Machining Different From 3D Printing?
Compared to 3D printing, small batch CNC machining provides a higher precision (±0.0001 inches) and better surface finishes. Small batch CNC machining is best suited to end use parts and functional prototypes. On the opposite, 3D printing is great for rapid prototyping of complex geometries.
What factors affect the cost of small batch CNC machining?
Cost is highly dependent on the material you choose. There are also other factors like— what tolerances you need, how much setup time you have, what is the batch size and how complex is your design.
What are setup requirements for small batch CNC machining?
The setup process begins by taking CAD design and converting it to machine readable input, G-code. After this we select the correct tools and then fasten the workpiece accordingly. Special programming and machine calibration are also required for every new batch to reach the best quality.
