Anet A8 Pen & Scraper Holder by ShaneAPowell

Last crawled date: 3 years, 1 month ago

Remixed to mount to the front where the blower fan goes, or right on top of the blower fan. I don't need a pen or scraper mount very often (just for PCB prototyping), so removing the blower fan when I need to install this is not inconvenient. YouTube videos still to come.
Why:
I've been using the LaserPrinter PCB etching method for a while now, and it works well. But, I figured since I have a new Anet A8, I should be able to use it to "Draw" out my PCBs. Now, I can use a pen/marker to draw an etch mask over my traces. Or use a piece of hardened steel to scrape off a PCB Board covered with mask to expose an "Isolation" route.
Components
Base: Bolts to the front of the extruder fan.
Carriage: Holds the pen or scraper
Brace: added strength to the A8 carriage bracket.
Parts:
2 x Traxxas T/E Max A-Arm screws. 3mmx70mm (Part #5161).
2 x springs from retractable pen
2 x 20mmx3mm screw -> Pen Holder
2 x 3mm nut -> Pen Holder
2 x 20mmx3mm -> Base to Printer Carriage & blower Fan
2 x small 12-13mm OD washer -> between base and fan
Assembly:
20mm screw -> Base -> 12mm washer -> Blower Fan -> Printer Carriage
Brace
The brace is just a simple 55x20x5 block. It gets wedged above the extruder motor to add a little stability to the flex of the metal carriage bracket. (see photo). It actually seemed to do the trick.
Print:
25% infill
3 walls
0.1 layer height
Tips:
The guides on the carriage were a nice fit on the pins, but a little too snug for a smooth glide. To improve the movement of the carriage on the pins, I used my electric drill to spin the pins inside the carriage for about a minute. The friction of the pin spinning in the carriage hole helped aligned the bore better, and increased the hole size a tiny amount for a little better play.
For scraping the copper with the drill bit, the pen spring was still enough to provide a nice scraping force. Very precise Z Control was necessary to push down enough on the bit to use the full force of the spring.
Large washers between the fan and pen base were very necessary and helped reduce any warping of the base. This warping was affecting the up-down smooth travel of the carriage. If you're getting binding on the slide pins, be sure to try washers here.
Mounting the base to the front of the fan is convenient, but it does induce a little flex which can cause the carriage to bind a small bit. Removing the fan, and mounting the pen base directly to the metal bracket is by far the most stable and smooth.
Problems:
The only real problem so far is that with the stock A8 220x220 bed, the position of the pen relative to the extruder tip means I lose about 60mm of Y axis depth. I easily fixed this by moving the piece of glass on my build plate down the Y axis and re attaching it with the binder clips on the sides (skipping the 1 clip closest to the HOME position).
Plans:
Another base design to mount to back of carriage for better stability.
Videos:
https://youtu.be/C9f2XlPntug (Short clip of PCB Traces). I need to work on my FlatCAM knowledge to get this drawing just right.
https://youtu.be/ek8bC_pFCbA (Short cip of PCB Isolation Routing).
July 14 2018: Added small hole recesses to base for more common 20mm length screws.