Why use Shapelid for custom online CNC machining services?
Shapelid provides a custom online CNC machining service to engineers, product developers, designers, and more through our vetted network of 10,000+ suppliers. Our highly qualified and certified machine shops can make any custom design, simple or complex. We offer rapid machining, small-batch machining, and high-volume production, with all orders serviced by Shapelid from end to end. Upload a CAD file to the Shapelid Instant Quoting Engine® to get a price, lead time, and design-for-manufacturability feedback on your custom CNC parts. Our fast CNC machining capabilities include services for metals and plastics and flexible production and shipping options to meet you at the perfect price and product development stage. Your price for CNC-machined prototypes includes tariffs and shipping for standard parcels.
Shapelid assures the quality of your machined parts with our ISO 9001:2015, ISO 13485, IATF 16949:2016, and AS9100D certified quality management system, ITAR registration, and options to add inspections, hardware traceability, material certifications, and CoCs. We accept technical drawings and have support teams to ensure you get quality CNC-machined parts on time.
CNC machining tolerances
Feature | Description |
|---|---|
Maximum Part Size | Milled parts up to 80” x 48” x 24” (2,032 x 1,219 x 610 mm). Lathe parts up to 62” (1,575 mm) length and 32” (813 mm) diameter. |
Standard Lead Time | 3 business days |
General Tolerances | Tolerances on metals will be held to +/- 0.005" (+/- 0.127 mm) in accordance with ISO 2768 unless otherwise specified. Plastics and composites will be +/- 0.010”. |
Precision Tolerances | Shapelid can manufacture and inspect to tight tolerances, including sub +/- 0.001" tolerances, per your drawing specifications and GD&T callouts. |
Minimum Feature Size | 0.020” (0.50 mm). This may vary depending on part geometry and chosen material. |
Threads and Tapped Holes | Shapelid can accommodate any standard thread size. We can also machine custom threads; these will require a manual quote review. |
Edge Condition | Sharp edges are broken and deburred by default |
Surface Finish | The standard finish is as-machined: 125 Ra or better. Additional finishing options can be specified when getting a quote. |
CNC Machining Design Guidelines
CNC machining design guidelines help engineers and product designers create parts that are cost-effective, accurate, and easy to manufacture. The first step is to optimize part geometry for machining. Avoid overly complex shapes unless necessary, and design features that can be produced using standard cutting tools. Ensure that walls have a minimum thickness of around 0.8–1.0 mm for metals and 1.5–2.0 mm for plastics to prevent warping or vibration during machining. Using uniform wall thickness also helps maintain structural integrity and reduce machining time.
When designing holes and pockets, match them to standard drill and end mill sizes to reduce tool changes and production costs. For example, hole diameters should typically be larger than 1 mm and have a depth no greater than four times their diameter for best machinability. Sharp internal corners are difficult to machine, so incorporate fillets with a radius that matches standard tool sizes, such as 3 mm, to improve tool access and surface finish. Where possible, design with larger radii to increase cutting tool life.
Material selection is another key factor in CNC machining design. Softer materials like aluminum and plastics machine faster and with less tool wear, while harder materials like stainless steel or titanium require slower speeds and more durable tooling. Choosing the right material for your application impacts both cost and performance. Consider machinability ratings and how the chosen material will interact with cutting tools, surface finish requirements, and post-processing needs.
Lastly, consider tolerances and surface finishes early in the design process. Tight tolerances increase machining time and cost, so specify them only where functionally necessary. For most CNC machined parts, a tolerance of ±0.1 mm is sufficient, but high-precision applications may require ±0.01 mm or better. Similarly, finer surface finishes require additional passes or polishing, which increases production time. By following these CNC machining design best practices, you can reduce manufacturing costs, improve part quality, and ensure efficient production.
CNC Machining materials
How does CNC machining work?
CNC machining is a manufacturing process that uses computer-controlled machines to precisely cut and shape materials such as metal, plastic, and wood. It begins with a digital 2D or 3D design created in CAD (Computer-Aided Design) software, which is then converted into G-code using CAM (Computer-Aided Manufacturing) software. The G-code provides exact instructions for tool movement, cutting speed, spindle rotation, and tool changes, enabling the CNC machine to produce parts with exceptional accuracy and repeatability.
Once the program is loaded, the CNC milling machine, CNC lathe, or other specialized CNC equipment automatically guides cutting tools along programmed paths to remove material from the workpiece. This can include milling, turning, drilling, grinding, or routing, depending on the part design. Advanced multi-axis CNC machines (such as 5-axis machining centers) can move tools and workpieces in multiple directions at the same time, producing complex geometries and high-precision components in a single setup.
After machining, parts often go through quality inspection and finishing processes to meet strict tolerances. CNC machining is widely used in aerospace, automotive, medical device manufacturing, and electronics because it offers high precision, fast production speeds, and the ability to work with a wide range of materials. By combining automation with advanced software, CNC machining transforms digital designs into production-ready components efficiently and cost-effectively.
What industries use CNC machining?
CNC machining is a cornerstone technology in the aerospace industry, where components must meet extremely tight tolerances and endure harsh operating conditions. It’s used to produce aircraft engine parts, structural components, and custom tooling from high-strength materials like titanium and aluminum. The precision and repeatability of CNC machining ensure that aerospace manufacturers can meet strict safety regulations and maintain consistency across production runs, whether for commercial, military, or space applications.
In the automotive industry, CNC machining plays a vital role in manufacturing engine components, transmission parts, suspension systems, and custom prototypes. CNC milling and turning allow automakers to rapidly produce both mass-production parts and custom, high-performance components. From prototyping new designs to producing spare parts, CNC machining helps the automotive sector reduce lead times, improve quality, and optimize manufacturing costs while maintaining the flexibility to work with metals, plastics, and composites.
Beyond aerospace and automotive, CNC machining is widely used in medical device manufacturing, electronics production, defense, energy, and industrial equipment. In the medical field, CNC technology produces surgical instruments, implants, and diagnostic equipment parts with high precision and biocompatible materials. Electronics manufacturers rely on CNC milling for heat sinks, enclosures, and delicate mechanical parts, while the energy sector uses CNC machining for turbines, valves, and drilling components. Its versatility, accuracy, and ability to handle complex designs make CNC machining an essential process across multiple global industries.
What is history of CNC machining?
The history of CNC machining dates back to the late 1940s and early 1950s, when manufacturers began developing numerical control (NC) machines to automate machining operations. These early NC machines used punched tape to feed instructions into lathes and mills, allowing operators to produce parts more consistently than with manual controls. The U.S. Air Force played a key role in funding NC technology to meet the aerospace industry’s demand for high-precision, complex components.
By the late 1960s and 1970s, NC evolved into computer numerical control (CNC) as computers replaced punched tape systems. The integration of digital computers allowed for more complex programming, faster setup times, and better precision. With the rise of CAD/CAM software, engineers could design parts digitally and directly generate G-code for CNC machines. This revolutionized manufacturing by reducing manual programming and enabling multi-axis machining for intricate geometries.
In the 1980s and beyond, CNC machining became a global manufacturing standard across industries such as aerospace, automotive, medical devices, and electronics. Advancements in multi-axis machining centers, automation, and high-speed cutting tools have continued to expand CNC capabilities. Today, modern CNC machines integrate with Industry 4.0 technologies, including IoT sensors and AI-driven optimization, making CNC machining faster, more precise, and more cost-efficient than ever before.
