Friday, May 22, 2015

Cabinet for my Printrbot Simple Metal 3D Printer

ABS plastic can be sensitive to air currents while printing. A cool gust of air from an A/C vent, open window or ceiling fan can cause a part to warp or lift from the bed. Living in Texas we have the ceiling fan running in our home office all the time so it was a must for me to build an enclosure for my Printrbot Simple Metal printer. I also wanted to keep my 3D printer from getting dust build up on it. I've read that dust can get in the hot end and cause clogs.

I started with a wooden platform made out thin hardboard on top of MDF. Then I built the upper part of the enclosure out of plexiglass and aluminum channel. I purchased the plexi and aluminum channel from Lowes. The aluminum channel is 1/16" x 3/4" x 3/4". I bolted the whole thing together with #8-32 screws. The build chamber dimensions are 15"H x 20"W x 22"D.

I 3D printed some screw down feet for my Printrbot so it doesn't move around inside the cabinet. You can download the design for the feet here:

The whole front of the enclosure is a hinged door. Magnetic door catches keep the door closed.

The top of the cabinet is also hinged and can be opened. 

My Printrbot has a heated print bed so it uses an ATX power supply from a computer. It has a bunch of extra wires that aren't used by the printer so I made a hollow area underneath to hide all the extra wires.

The power supply is mounted in the corner so it takes in and vents air outside of the enclosure so it doesn't overheat.

I made a spool holder out of a 6" Lazy Susan bearing and a piece of plywood. I put a 3/8" carriage bolt in the center of the spool holder turnable which is used to secure the filament spool to the holder. I used some #6-32 stand-offs and #6-32 screws with the heads cutoff to allow the turntable to sit an inch above the lid so it can rotate. This also allows the turntable to be lifted off when the top lid needs to be opened.

Then I designed a knob and cone that secures the filament spool to the turntable. You can download the design here:

Here is a more detailed shot showing the path of the filament into the cabinet. I drilled a .25" hole in the top panel.

Next I added LED light strips around the top of the cabinet to light up the inside. The strips are power by +12vdc so I was able to hook them up to the Printrbot ATX power supply. The lights turn on when the printer is powered up.

Here is the printer in action inside the cabinet:

There one thing I'm still working on. I put an exhaust fan in the upper right corner of the back wall of the cabinet. I don't want the cabinet to get too hot inside but I also don't want the fan to run all the time or run at full speed so I'm designing a small circuit that controls the fan speed based on the temperature inside the cabinet.

UPDATE 2015-08-18

I mounted my OctoPrint print server running on a Raspberry Pi to the side of the cabinet. I also added a 20x4 character LCD display that shows useful info about the printer.

Thursday, May 21, 2015

Awesome tool for getting 3D prints off a heated bed

I have a Printrbot Simple Metal 3D printer with a heated bed. Lately I have been printing with ABS plastic which requires hairspray to get the prints to stick to the bed without warping. While this works great it to keep the print stuck to the bed it can be difficult to get the prints off the bed without damaging the print or the Kapton tape. I've tried an X-Acto knife but it digs into the Kapton tape. Paint scrapers are usually too thick and have a blunt edge that can't get under the print. Some people use pliers to grasp the part and pull it off but I've found the pliers makes marks on the part when you grab it. My wife recommended a tool that we use with our Silhouette Cameo vinyl cutter:

It's made by Cricut and they call it a Spatula Tool. It has a very thin front edge that is good for getting under prints and then it tapers up a little bit to make it stronger.

I slide it in under a corner and work it around the print and then lift up a bit and the print pops off. It looks like the spatula we have is an old model but I did a search on E-bay and there are a several of them for sale for less than $10 bucks. Just search for 'Cricut Spatula Tool' and look for one with a green handle. Cricut's has a new spatula design but is a little smaller and I don't know if it works as well. I might buy one just to try it out.