This Old Machine: Re-purposing an Engraver as a 3D Printer

I got ones with anti-backlash nuts, 18" long for about $75 each
Helix Linear Technologies

 

Bowden tube. Fits in with later plans.

 

Anybody got a pusher type they are fond of that they would be willing to print parts for me that works well with NEMA 14? I have 4 motors to use as pushers and a lot of bearings and I can cut the metal pusher gears pretty easy.

 

A 26 mm square (1.024"). The centering boss is 22.01 mm diameter (0.866").

 

yeah the more common 17 size is a 31mm square. For the NEMA 14 stepper 700 g*cm holding torque minus 90 g*cm detent torque is 610 g*gm ~= 6 N*cm ~= 8.5 oz*in running torque at low speed. Pretty marginal, but it might work. Can't hurt to try.

If you have a pusher model you like that works well with a NEMA 17 I can modify the model to fit a NEMA 14.

 

I got all the lead screws swapped out for 8 mm diameter metric lead screws, 8 mm lead and extended the Z axis travel to 200 mm, even though I can only use about 125 mm of that due to the gantry clearance. So that gives 0.04 mm full step resolution and about 0.0025 mm (around 0.0001 inch) with 1/16 microstepping. 450 RPM on the steppers gives 60 mm/s. I will have to experiment some once I get it wired up to see how fast the smoothie can move it without skipping steps.

In the process of mounting the lead screws I discovered I really don't like tapping stainless steel lead screws on my tiny lathe, it is probably worth it to pay for the machining at the factory, since they seem to have about a week of lead time anyway.

The machine's usable travel between the Y guide rails with a hot end almost exactly matches the glass sitting on a regular sized 214 *214 mm MK2b heated bed. Starting work on the wiring now. I think I now have all the components needed to get it running here except the pusher for the extruder.

 

Have about 2/3 of the wiring done, is anybody up for printing me some extruder mounting bracket parts? I have are design ready. Also have a Ar 196 and a Supermarine Walrus model ready to go when I done this printer done.

 

Distance between hot ends and filament drivers is adjustable

Before adding pinch gears, bearings and adjustment spring / screw.

Thanks Nick for the nice printed brackets! I'm much closer to printing now that I have the hot ends mounted. Was the insulation wrapped around the heated blocks with tape really necessary? I took it off. Maybe I will stick a washer between the heated block and the fans to reduce heating the fan shroud from radiation. Need a couple more M6 nuts to do that. Then on to thermocouples and fixing a problem with not enough serial channels to run both thermocouple boards and the display.

 

Little bit of life getting in the way, removing alpha crapware called Windows 10 by restoring a 1.5 year old backup. On the printer I still have to finish wiring the thermocouple cards and LCD, then tell the software where everything is plugged in before I can get it moving and heating. Finally got a DLP projector in the house so playing with light cured resin is a future possibility.

 

Look, Squirrel!