Category: Complex Machining

Milled buckle

Here is a milled aluminum buckle still attached to the blank it was machined from. If you look closely, you can see both striations and faceting on the surfaces from the cutter. The striations come from the “stepover”; the amount the ball nosed cutter is moved over for each successive traverse across the part. The faceting comes from approximating the curve of each traverse by moving the cutter in thousands of tiny straight line moves. Both of these parameters can be set during programming. A smoother less faceted surface comes at the expense of longer cutting time so a compromise is chosen depending on the needs of the customer. This part was cut with a 0.0938″ diameter ballcutter with a stepover of 0.005″ and approximates the curve within 0.001″. The cuts required 1/2 hour run time per side including picking out the corners with a smaller cutter.

Production jig

Here is an aluminum part used in a production line to make gloves. The programming and machining are straightforward except for the curved track that wraps around the tip of the part and required milling in two setups using small cutters. The parts are about 4″ long.

Complex stainless steel parts

This five part assembly is machined from 303 stainless steel and is about 4″ across the widest span. The main part is hollow with a wall thickness of just under 0.100″. Two days were needed to program and cut these parts.

Aluminum cover plate

The part is about 7″ by 10″ and approximately 3″ thick. It was a challenge to machine because the wall is only 0.200″ thick and required special measures to keep vibration and distortion under control. Over 30 programs were needed to run the part and the total runtime and programming time was almost 40 hours. The material is Alumec 89 aluminum. The raw block weighed almost 25 lb (11.5 kg) and the finished part is 14 oz (390g).

1. TOP VIEW: The part has been milled, handworked and fine glass beaded. The logo was milled using 1/32″ diameter cutters and stands about 0.150″ tall. It is proud of the surface by about 0.025″

2. TOP VIEW #2: A view from the other end

3. UNDERSIDE VIEW: This side was milled first.

4. HALF MACHINED IN THE MILL: This part is being milled in my Haas Minimill. The underside is already finished and the first 2″ of the top is roughed. The red stuff peeking out at the corners is Plasticene used to dampen the vibration as the part is milled. The Plasticene and milling strategy of cutting it in 2″ sections was the only way to keep the part from self destructing during cutting. Blending of successive sections was done by dropping the cutter in small increments until the new cuts just kissed the previously milled surface.

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