The sole purpose of CNC machine jaws is to grip the workpiece or component better in the CNC machine. Despite their simple purpose and designs, CNC jaws are a critical part of a CNC machine workshop that help ensure the safety of machining operations. They are also vital in preventing a workpiece from moving during machining processes.
The positioning of machine jaws is influenced by tool force. The direction of the force placed on the workpiece determines how the piece needs to be secured, or how tightly it should be held. A firm grip on the workpiece is critical for the end product to meet the desired specifications. Soft jaws that do not adequately secure the workpiece risk it moving under force and the resulting component being out of spec. Inadequate soft jaws also compromise operator safety, and loose workpieces can damage a CNC machine leading to production downtime.
CNC jaws, which sometimes also include chuck jaws that secure workpieces in lathes, come in both standard and custom shapes. They are generally categorized into three separate categories:
- Base jaws: Sometimes called master jaws, they are attached to the body of a machine and can be moved towards or away from the workpiece being machined. The base jaws carry any additional soft or hard jaws with them.
- Hard jaws: Also known as step jaws, these are typically made of hardened steel to use with the most intense tooling processes and to make them last. They are usually not customized. Such jaws are designed with beveled teeth or edges to properly grip the required component.
- Soft jaws: CNC soft jaws are usually made of materials such as aluminum, bronze, and cast iron and can be ordered in standard sizes, or customized to specific dimensions as needed quite easily. Soft jaws make it easier to hold components that are otherwise difficult to fixture with standard vise jaws during machining.
Aluminum is a preferred material for designing CNC soft jaws. It is a relatively soft metal and offers good mechanical strength and the ability to conform to the contours of the workpiece without damaging it. It is also easily cut to the needed sizes and machined as needed.
Designing CNC Soft Jaws
To fit an odd-shaped component, soft jaws can be customized to create an exact fit. However, customization and designing of CNC soft jaws take time and labor. Engineers use Computer Aided Design (CAD) files to create a 2D or 3D copy of the inverse of the component and then use Computer Aided Manufacturing (CAM) software to machine the design on their CNC machines.
Starting bar or plate stocks of aluminum are usually slightly larger than the size ordered. Machinists will need to reduce a round bar to the desired size on a lathe or cut the jaws to match the actual material size. The jaws should be cut deep enough to ensure a secure grip during machining. Once CNC soft jaws are fabricated, small modifications are further made as per the required specifications, or they can be modified by the operator to ensure a secure fit as needed.
Owing to the extensive work involved in developing CNC soft jaws, it is critical to select the right material. Aluminum is often the preferred metal over iron or bronze for making CNC soft jaws due to its combination of properties:
- Lightweight: The light weight of aluminum makes it easy to quickly set up CNC soft jaws.
- Strength: Soft jaws made of high-grade aluminum offer increased gripping power at higher speeds.
- Relative softness: Aluminum is easier to cut, thereby reducing tool wear. The relative softness of aluminum makes it easy to customize CNC soft jaws to fit odd-shaped workpieces. They also pose less risk of damaging finishing on workpieces.
Designing CNC soft jaws with aluminum requires quality material—bar stock or plated sourced straight from the mills or verified remnants from a trusted metal supplier. You also need precision cutting tools to accurately cut the aluminum stock to desired dimensions as per design blueprints.
Partnering With Industrial Metal Service for Quality Aluminum
At Industrial Metal Service, our vast inventory has 500,000 pounds of in-demand aluminum alloys in different shapes and sizes, both new and remnant. We source certified aluminum from major mills such as Kaiser. The composition of all our remnant aluminum is verified using x-ray fluorescent scanners to ensure you receive quality material to match your production standards.
Aluminum procured straight from the mill is rarely the right length or dimension for immediate welding, shaping, milling, and other machining operations. We offer custom cut-to-order sawing services with industrial-quality sawing equipment to make sure that you receive precision-cut aluminum stock ready to be used for designing CNC soft jaws. With our faster turnarounds on precision cutting, along with our reliable and trusted delivery services, we help you get your custom-cut aluminum stock right at your workshop.