Making AR-15 Lower Receiver and Semi-Automatic 308 Lower Receiver Fixtures with VoluMill
Central Screw Products recently upgraded our fixturing capabilities by adding a Vero-S Zero Point Positioning System from Schunk. We have spent the past month developing our fixtures and systems to integrate into the Vero-S. By doing so we are looking to reduce our set-up time between jobs, and take the first step into automating a new set of jobs.
In order to incorporate the Vero-S we had to redesign and develop our fixturing for our AR15 lower receiver and semi-automatic 308 lowers. We have spent the past month tweaking the fixtures, and this past week we started to cut them. There are times we wish this all went faster, but there is limited machine time in our busy shop!
Central Screw Products uses CAM software from Gibbs Cam. In addition, we work with our friends at Great Lakes Cam and they provide us with support for the software. We feel the support is paramount to be on the cutting edge of machining. We decided to use our brand new Haas VF-2 to manufacture the new fixtures for the AR-15 and 308 rifles. This is where the excitement begins.
Great Lakes Cam advise that we use a plug-in for Gibbs Cam called VoluMill. The VoluMill plug-in is a machining approach where we define the max engagement of the cutter. Because we are never taking a full cut with the tool we can go much faster with the tool, reducing our machining time. As an example for our fixtures we were able to increase our feed over three times from our normal feed and increase the depth of cut by 5 times. Our machining time was reduced to a quarter of what it would be with regular roughing cycles.
Producing the code is half the story, then we needed to machine the part. The Vero-S gives us a solid hold on our fixture, along with perfect repeatability. This allows us to take the fixture out to check it, and put it back in. It also allows us to crank the speed up without worrying about the part slipping. On our new VF2 we bought the high speed machining function. This is an algorithm that runs in the background that controls the acceleration of the machine when it is taking cuts. If you can visualize a machine moving in a single direction, decelerating to a stop, turning 90 degrees and accelerating back to full speed is not good for a cutter, or for the machine. It would be better to move through an arc, or slow down at the corner. The high speed machining function from Haas helps the machine to do this.
So by coupling these three things together, a new software algorithm, a new machine with a high speed machining algorithm, and solid work holding, we were able to cut our new fixtures for the AR-15 lower receiver more precise and quicker than ever. In addition, we can take the fixtures out, and put them back in and repeat immediately.
Attached to the article are some pictures of the process. If you have any questions, please don’t hesitate to contact us. As a final thought, at CSP and DGW we put together the entire system. We know that it is not a single part of the process that makes it great, but how the processes work together. Just like a good team, better as a sum of the parts than the individual components, putting the process together allows us to produce components effectively with the highest quality.
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