To Prep or Not to Prep (The Workpiece)…That is the Question!

There are many different clamping devices and mechanisms for CNC milling tasks. Examples include fixed-jaw vises, self-centering vises, dovetail holders, modular-serrated holders, etc. It is a long list.?

What dictates the type of fixture required? The factors are often force, rigidity, accessibility, and deformation. ?

• Clamping Force:?You may require a device with a high level of clamping force to compensate for aggressive machining techniques or a clamping device that allows you to scale back in softer material.
• Rigidity:?A device designed to manage and mitigate vibration.
• Accessibility:?4 and 5 Axis machining applications require access to 4 or 5 sides of the work to take full advantage of the technology.
• Deformation:?Poorly managed force and bulky devices can deform the material, negatively impacting high tolerance work.???

These factors can be mutually exclusive. As an example, too little clamping force in hard material may jeopardize rigidity. ?

Depending on the application, some devices require workpiece preparation for compatibility.?Workpiece preparation can also solve manufacturing challenges, such as machining hard material, where eliminating wear and ensuring process reliability are very important. For applications where workpiece deformation is a concern, workpiece preparation can be used for part locating and torque limiting in softer materials.???????

Workholding manufacturers should have clear guidelines for ensuring process reliability. For example, the tooth serrations on an “X” Series, self-centering vise from 5th Axis, are rated 35HRc. Materials harder than 35HRc will require you to take advantage of the vise jaws patented, integrated dovetail feature to guarantee a reliable process. Utilizing dovetail technology is an excellent example of workpiece preparation.?

Increased Reliability with Dovetail Holders

Process reliability is critical in automated manufacturing. Lights out operation is vastly different from a manned operation, especially where components without clear guidelines?or?an alternate option for preparing the workpiece are dangerous and often unreliable.?They wear.?

Workholding preparation is required when the clamping component wears to the point where rigidity is lost, vibration is increased, and either workpiece movement or total failure, “throwing a part” occurs. Unfortunately, it is often difficult to predict when these failures will happen. In these situations, dovetail fixtures are accepted as the “go-to” solution for the following reasons.?

• Durability:?Dovetails are known for their inherent and tensile strength.?
• Longevity/ Reliability:?The mating surfaces being used for the clamping operation are smooth. Wear is reduced to almost nothing.
• History:?There are claims that dovetails were used in ancient Egypt and in furniture production starting as early as the 1600s.?
• Precision:?Dovetail holders often have features that allow you to locate your work precisely.??

Are experiencing any of the manufacturing challenges mentioned above or considering a move into automated manufacturing?

Contact me today for a free process and workholding systems review and consultation!