Introduction

The robotics industry is being propelled by advanced manufacturing techniques. Apart from high quality hardware, robots also require precise manufacturing to ensure the accuracy and durability of their application and function. CNC machining is one such manufacturing solution utilized to fabricate robot parts. It pre-programs the speed and position of machine tool functions and runs them via software in predictive cycles, without requiring any involvement from human operators.

CNC Machines and Robotics

CNC machines are operated through numerical control, where a software program controls an object. The language used by CNC machining, which is also known as G-code, controls the behaviors of a corresponding machine, such as speed, feed rate and coordination.

A CNC machine, when activated, programs the desired cuts into the software and dictates to the corresponding tools and machinery to perform specified, dimensional tasks. In this sense, it works like a robot.

The production of parts through pre-programmed software is mostly automated. The dimensions of a given robot part are set into place using computer-aided design (CAD) software and converted into the finished product with computer-aided manufacturing (CAM) software. The entire process enables a consistency in parts production that would be extremely challenging to replicate manually.

For metal fabrication and steel applications, including robot development, there are CNC systems purpose-designed to deliver the perfect finish across various types of metals. For instance, ShopSabre’s CNC systems are equipped with the necessary software and components that turn existing industrial designs and drawings into cutting files.  CNC machines include production cutting options that hold parts in place and machine them accurately with high-quality edges and corner detail.

Tools

CNC routers and plasma systems are powerful tools for robotic fabrication. A CNC router can run any number of custom programs to cut and slice with laser-like precision. A CNC plasma system allows computer-guided cutting of thick material, ensuring clean, sharp cuts.

To give an example, Aspire’s software solution allows manufacturers to create and cut parts on a CNC router. Robotics manufacturers can leverage 3D design tools to create 3D relief models and machine them with 3D machining strategies. There is also the option to couple 3D modeling tools with 2D design and editing tools to create 2D and 3D parts from scratch, as well as import and edit external 2D and 3D data.

CNC plasmas offer more capabilities than typical plasma cutting machines. They are most commonly used to cut aluminum, brass, copper and other robot fabrication material.

Materials

Steel

Steel is both a strong and an inexpensive metal. Unhardened mild steel yields at 30,000-50,00 psi, and can be easily hardened to 100,000 psi for structural purposes. For tooling, steel can be strengthened to nearly 300,000 psi. Steel is several times stronger than aluminum but not as easy to work with. It can be used for smaller parts, but not as a main structural metal.

Aluminum

Aluminum is about one third as heavy and strong as steel (density 2.7 gm/cc, yield point 10,000-40,000 psi). Being malleable and ductile, aluminum can be more easily machined into robot parts. It is dust-resistant but can corrode in wet environments, so poses a durability issue if the robotic application involves contact with water.  

Copper and brass

Brass are copper alloys that can also serve as structural materials for robot parts. Brass has the roughly the same density as steel and about two-thirds its strength (density 8.4 gm/cc, yield point 25,000-60,000 psi). Brasses are easily to machine.

Some copper alloys resist corrosion very well. They are a replacement to steel when corrosion-resistance or the non-sparking and non-magnetic properties of copper alloys are significant enough for the project to justify the cost, which can be up to five times the cost of regular carbon steel.

Titanium

Exotic and employed in high-tech applications, titanium has half the density of steel (4.3 gm/cc), although some alloys can match the strength of steel (yield over 150,000 psi). It is highly corrosion resistant and has a high melting point.

However, titanium is also quite difficult to machine and can be cast only with very specialized equipment. It is the choice of metal for unique robotics use cases that require lightweight and high strengths, such as in aerospace applications.

A composite may also be considered for its weight-to-strength ratio. It is ideal for creating mockups. The composite can take the form of laminated material that combines plastic, wood, paper or metal; any material that uses fiberglass and a resin; and any material that uses carbon and graphite for strength.

Aluminum and steel are the most common metals for robot parts fabrication. Regardless of the type of metal use, construction generally follows two approaches:

  • A frame serves as the base of the robot. It can be box-shaped or flat. A box frame is usually used for bigger-sized robots or those that need additional support for heavy components.
  • A shaped base, which is a piece of metal cut into the shape of the robot. The metal needs to be rigid enough to support the weight of components without flexing.

The Future

Modern CNC machines are high precision products manufactured at scale. Their capabilities continue expanding to reinforce their utility in robotics parts manufacturing.

Even as CNC machines become more advanced than before, their prices have also dropped, making them more accessible to small and mid-sized manufacturers. They have also become easier to use, allowing users to set-up and utilize a CNC router or plasma cutter without requiring any specialized expertise.

With automation and computerization integrating into manufacturing, CNC machining has a bright future ahead for both traditional manufacturing applications and robotics fabrication. And even though CNC machines face competition from 3D printers, CNC tools have the advantage of subtracting materials for large pieces to create a robot part, while 3D printers add materials. They are expected to continue being embraced by manufacturers seeking to boost productivity and precision in a convenient and affordable manner.