Archive for October, 2012

New Vector Grid

Saturday, October 20th, 2012

Laser cutter vector grid

I recently broke down and ordered a new vector grid for my Epilog Mini-18 laser cutter. First, I was happy to find that it wasn't as expensive as I had imagined. Second, I was pleasantly surprised that the new vector grid was a considerable upgrade over my now 7-ish year old very heavily used vector grid, seen above (I really need to clean the old grid).

Laser cutter vector grid

The new vector grid has a nice aluminum frame and the edges of the honeycomb are glued in place, keeping the comb rigid and flat. The new comb seems a bit stiffer than the original as well, though I'm uncertain if that's more due to wear on my old grid or a difference in material or metal gauge on the new grid. Either way, I'm loving the new grid!

Using Delrin Clips for Assemblies

Thursday, October 4th, 2012

Delrin clip mechanism

So to make it easier to assemble some of the enclosures I make I recently experimented with making some clips to hold the things together instead of using the ubiquitous nut and bolt based T-slot construction method used in tons of laser cut assemblies. Some have integrated clipping mechanisms directly into the acrylic of the parts of the assemblies, and I really like that method, but I don't really trust flexing acrylic to not become damaged easily through normal usage, so I opted to go with Delrin based clips.

Delrin clip mechanism

They seem to work fairly well and have a couple advantages over nut & bolt T-slots:

  • You don't have to hold the nut in place while joining the parts and placing the screw, which can be quite annoying and require the assistance of some tape in some cases.
  • You don't have to worry about over tightening the bolts and cracking the acrylic.
  • It's quicker and easier to assemble and disassemble parts, as you just have to press in or pull out the clips once all the parts are in place.

There are some disadvantages too. The clips have a little bit of play to them, so the connections aren't rock solid like they can be with nut and bolt T-slots. I wouldn't use clips on projects where mechanical rigidity is key, but they're pretty attractive options in a lot of other cases.

BeagleBoard Rev C Enclosure

Here's an example of a completed project using the clips. It's an enclosure for the BeagleBoard Rev C and you can grab the design files here if you want to take a look at the clip and slot designs or use them yourself.