A vacuum chuck is a plate-like or sheet-like pad which is used to mount bowls to a CNC lathe for light turning and finishing without marking or marring the surface of the work piece. The vacuum chuck is similar to fixtures and clamping systems for they enhance the effectiveness and productivity in manufacturing. The vacuum chuck is helpful especially for rapid sheet work such as signs and electrical panels.
The mechanism of a vacuum chuck, or a vacuum table, is significantly different from other work holding systems like fixtures and clamping systems. That latter applies power vices to secure a work piece while the vacuum chuck sucks the work piece tight to the vacuum table. The vacuum chuck is a plate-like or a sheet-like pad with grid patterns on it.
To hold the work piece tightly, the piece will be placed on top of the vacuum chuck first, and then the vacuum pump under the chuck is turned on to suck the work piece downward to the chuck and it is hence clamped in place securely. Because of the feature, the vacuum chuck is the best clamping system for thin and large sheet materials.
When applying the vacuum chuck or the vacuum table as the work holding system, to best work with it, here are some features to bring up for people to refer to so that it can be best worked with.
First thing to know is that the vacuum power has its limit. The exact stat of the strongest vacuum power is roughly 14 pounds of downward holding force per square inch. The cause of the limit is that, it is in fact the atmospheric pressure that actually presses the work piece down onto the chuck. The stronger the air pressure is where we locate, the more powerful a vacuum chuck is.
The second note is to make sure that small and sharp cutters are used. Small cutters exert less torque and side forces and they hence reduce the chance of throwing the work piece off the vacuum chuck. Sharp tooling reduces side load and again, it reduces the chance that the piece fall off the chuck. To reduce the chance for the piece to fall off, it is also crucial to void using high helix end mills. The importance of choosing the cutter cannot be emphasized enough. The use of low helix cutters is able to reduce the chance that the work piece fall off the vacuum chuck when the piece is taking certain aggressive machining operations.
Another thing that is noticeable when clamping work pieces with a vacuum chuck is the releasing of vacuum. When the pieces are cut or milled, the work can possibly breach the vacuum so that the pieces are loose and slide off the table. Gaskets are sued as a layer to cover up any rough holes or cuts and limit the bleed off of vacuum. It is also important to keep the chuck clean; dusts or any other tiny substances between the chuck and the parts can break the seal as well.
The vacuum chuck work holding system is helpful when it comes to work pieces shaped in thin sheets of course, but it is vital to bear in mind that power vises or clamps are the measures with much higher work holding force. Regarding the materials to be secured, the vacuum chuck may sometimes be the only option for the task, but the clamping force is a limit to it to take machining with high intensity.
It doesn’t matter how big or small the work piece is. It is actually a matter of what process the part is going to work. For small parts, pieces can be milled in a bulk batch from a sheet. There are adhesive grid designs on certain types of vacuum chucks to better hold extra small parts firmly for more cuts. For big parts, vacuum chuck is the quickest and simplest way to hold sheet materials. Just make sure the vacuum table is well-maintained so that the parts can be tightly secured onto the chuck for machining.
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