We have begun work on a new robot that we call Aluminalis (more on the robot name and design at a later date). It’s a complex robot that will take us some time, so instead of waiting until we’re done, we’ve decided to keep everyone updated as we go.
The project involves over a thousand parts, most of which we designed ourselves. Here we are sanding various aluminum linkages on 220 sandpaper to achieve the uniform brushed aluminum look that we like. It’s no coincidence that the parts lying on the bench look like piles of bones. This is a biologically inspired robot.
As you can see from the previous photo, many of the parts in this project are small aluminum parts that require holes to be drilled a precise distance from each end of the part. To accomplish this, we attached a brass clamp to the vise in the vertical mill to create an improvised “mill stop”. We pushed the part up against the mill stop and then tighten the vise and bring down the mill spindle to drill the hole. This allows us to drill highly repeatable accurate holes very quickly.
We machined these crank shaft parts on our CNC Mill. The CNC cut the bone-like shape and drilled two of the holes, but the other two holes, which come in at a 90-degree angle to the first two, were drilled in a second operation on the vertical mill using the mill stop shown above. After drilling the transverse holes all the way through, we then tap the holes from each side with a #4-40 thread. This allows us to put tiny #4-40 set screws into the holes, which will hold aluminum shafts in place. The robot’s two crank shafts will involve sixteen of these parts.
This project also involves cutting many small 1/8″ diameter aluminum shafts to various precise lengths. These will be used in the crankshaft discussed above and as pivoting connection points for the robot’s many linkages. We tried different various methods to cut the shafts, such as snippers, table saw, and chop saw. But in the end, none of these were satisfactory in terms of accuracy, repeatability, and surface finish. We ended up using this “Duplicating Jig” and a 42 tooth razor saw. This method provides a good surface finish and is extremely precise and repeatable. This is really going to help. We’ll keep you posted as we make progress on this new robot. In the meantime, be sure to leave comments.