Aluminum Base Plate

I have been thinking about designing an anodized aluminum base plate for the Handibot to replace the HDPE one. My main reason for considering to do so would be to have some precise index locations that will hold up better over time. These index points could be thru holes like on the Kickstarter model or integrated features for the large template jigs like on the developer edition.

Before doing so I wanted to find out if the Shopbot team considered something similar and whether or not it was abandoned for any mechanical reasons such as thermal expansion differences with the HDPE. I am guesing an all aluminum version was considered but was not pursued due to costs?

If there was no reason not to do so I wanted to find out what the community would want to see in a next generation base plate?

I'll let the ShopBot guys chime in on why they picked what they picked, but I can say for a baseplate that is near the tool, I like them to be out of something millable, that way if the tool ever hits it, it doesn't matter.

At one point I had a base that had the exact opening of the cutting area of the Handibot on it. The problem with that is that if I wanted to cut something that was 6x8" the tool would have to travel farther than that to cut out that shape. It can do that, but with my 6x8" opening, I would have hit the sides of my jig. Because my jig was wood, this was fine, if it was metal, that would be a problem..

Does that make sense?

Hi Chad,

We did experiment with other materials such as phenolic and lexan. In the end, there wasn't enough of a performance difference to justify the cost. Certainly, there are materials that might last longer, but the HDPE is very durable and should last a very long time. The relatively low cost of the HDPE baseplate also allows developers to experiement and modify without being worried too much about cost. Even still, for some specialty applications, it might be worth further pursuing alternative materials as you've suggested.

David

Thanks for the input. I do agree that the current baseplate is very durable and a good all-around solution. One of the issues with the Handibot related to 3D machining is that for bit changes (rough and finish passes) you lose your reference point if you move the tool relative to the workpiece in order to do so. I built a jig that has holes match drilled to the baseplate. It works pretty well, but does lack a little accuracy. I have found the better solution is to take the time to change the bits from above without moving the tool.

My thought was that an aluminum plate with a set of precise holes could be matched to a jig that would allow very accurate repositioning for bit changes. I no longer think that is necessarily the best solution.

My current thought is to build a jig that the Handibot bolts down to with a work platform that is raised and lowered beneath it. This allows clearance for bit changes and potentially faster z-axis zeroing. This jig could also be used to accomodate different size lumber stock for feed thru type joinery operations.