In CNC routing or other sort of CNC machining, working with an expensive setup or workpiece is not all to make your project successful. You should also know the workholding technique to position and secure the workpiece in a place. Otherwise, the immense amount of force applied by the router on the tool won’t be withstood by the workpiece causing it to deflect from the path. Consequently, you will only end up getting a deformed or inconsistent product of no use. The importance of an accurate workholding system should, therefore, not be neglected.
So, in this article, I have mentioned some of the most used solutions to hold down the wood without vacuum while CNC routing.
- T-Slots – These are fixed to the CNC router/drilling table to quickly hold down the wood and begin the process
- Clamps – These are the most widely and commonly workholding tool in the market, used to secure and position workpieces to the T-slots or without it. A wide assortment of clamps of varying sizes and shapes that, in turn, suit your work size and shape, are available on the market
- Fixture Plates – These are also known as tooling plates and are either made of Aluminium or Cast Iron. However, steel plates are also available. Fixture plates are attached above the T-Slot table giving a new approach to the machinist to position and hold the workpiece. These plates have a grid of threaded holes for using precision dowel pins and fasteners for wood positioning. The grid enables workholding placement repeatable and easier.
- Vises – It includes two jaws with each being perfectly parallel to each other alongside having great strength. This basic workholding tool is typically fit for tightly gripping wood stocks and maintaining its perpendicularity while routing.
- Parallel Bars – These are mostly utilized with vises for workholding at a specified height off the vise’s bottom, giving enough space to the workpiece for edge routing, drilling or other CNC machining operations.
- Jaw Plates – These are placed in the outboard of vise jaws and are usually utilized to hold larger workpieces in place.
- V-Blocks – These are usually employed for holding cylindrical workpieces like bars, wood logs, etc. The design of V blocks is such that they allow quick and accurate location of the Y-axis center.
- Angle Plates – These are fitted to the slotted router table setup (made of cylindrical squares) to clamp the wood piece in a convenient position (at absolute right angle to the t-slot table) with respect to the router bit. These heavy angle plates are available in varieties of sizes on the market.
- Jigs – It not only acts as a workholding tool but also guides the CNC routing tool. The jig helps you secure, support, and place the workpiece accurately while guiding the tool in a specified operation. These workholders are usually attached with guides or hardened steel bushings (for machining tools). With jigs, you can control the motion and position of the router tool. The primary purpose of jigs is to allow repeatability and interchangeability while maintaining accuracy in the product manufacturing. When a product is duplicated, the original product is used as a jig to guide the tool to follow the same path to create exact newer copies of the original one.
- Fixtures – It is another workholding tool on the list, used to hold and position the workpiece for a particular operation. It, however, does not guide the router tool to the accurate position on the workpiece, like a jig does. The fixture only gives a reference surface for the workpiece to be held. The unique thing about fixtures is that every such tool is manufactured to fit only a typical part or shape. Locating and holding a workpiece in position is the ultimate purpose of using a fixture in a machining operation.
Not only CNC routing but fixtures can be employed in milling, shaping, turning, grinding, boring, planing alongside other multi-dimensional CNC machining applications.
Conclusively, there is no universal woodwork holding solution for CNC wood routing operation (or other CNC machining operations). What type of workholder you should use depends widely on the type of wood block you are working with. Being a professional machinist, you should determine the best-fit workholder for successful machining operations, thereby maximizing the spindle time, minimizing changeover requirements, and improving product output.
Your workholder selection should be based on the workpiece’s (here wood) diameter, weight, length, and shape. Also, the type of slicing and routing you do on the workpiece is also greatly managed by the workholder. Inaccurate selection of workholding tools may, therefore, result in a damaged throughput.
Irrespective of how expensive and advanced your CNC router is, if your woodpiece is not held tightly and properly in the required position, there is no way your project is going to work out successfully.