Archive for the ‘Info’ Category

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.

Epilog Laser Modules

Sunday, June 10th, 2012

Laser module

A couple months ago I had to replace the laser tube/driver on my 35W Epilog Mini-18.  It had slowly been losing cutting power for a few weeks before I had to get it replaced because I simply couldn't limp it along any more. I snapped a couple pics of the laser module before sending it back to Epilog to swap it out for a fresh one:

The entire module is housed in a big aluminum block and sits under 4 fans on the cutter for cooling.

The whole thing appears to be powered off the main 48v power supply and it connects to the motherboard via a standard Cat-5 patch cable.

Laser module

On the opposite end you can see the laser pointer module, used to adjust the optics and help you position the laser home position. Overall, these modules seem pretty well designed and pretty convenient if you're building a laser cutter. I'd love to be able to find laser module setups similar to this (air cooled, metal reflector tube, integrated visible laser pointer, integrated driver electronics) for a DIY laser cutter!

The Carbon Filter Experiment Postmortem

Wednesday, May 30th, 2012

Damaged active carbon filter

So apparently it's a really bad idea to use aluminum mesh as a container for active carbon! After sitting around for a couple weeks the aluminum screen became extremely brittle after reacting with the active carbon and the whole thing sorta fell apart. I'm going to probably be replacing the mesh cage with a basket made from perforated stainless steal when I've got some free time, after the Kansas City Maker Faire most likely.

A Look at the Epilog Mini/Helix Motherboard

Monday, October 17th, 2011

I nearly had a heart attack about 2 months ago when my laser cutter stopped suddenly whilst cutting some parts. Turns out that a component or two on the motherboard was fried.  I took this opportunity to snap some pics of the board out of my 5ish year old Epilog Mini-18:

Epilog Mini-18 Motherboard Top

Epilog Mini-18 Motherboard Bottom

As you can see, there's already been a little rework on this board before (bottom photo near u17). Looks like a PXA255 is the brains of the system and there's an FPGA on board as well (Altera EP1K100FC256).  The entire system is powered off a single 48 Volt 12.5 Amp power supply, so this board seems to provide all other regulated sources for the system.  It seems that a voltage regulator blew from the looks of the fried chip (top photo, U31, just left of the PXA255, appears to be an Linear LT3430).

Luckily, Epilog will send you a new motherboard without much hesitation and I had my mini up and cutting orders in no time. My new board's layout is pretty similar but has an additional daughter board with some big inductors on it, which I'd bet is a power supply fix for this board.

P.S. If your Epilog Mini or Helix dies suddenly, looks like there's an internal 5Amp breaker the motherboard is on that you can try and reset and there are some status lights on the motherboard indicating the rails that are up (48v, 5v, 3.3v, and 2.5V) so you can at least tell if everything's getting power.  Mine only had the 48V rail up after kicking the bucket.