Grbl Controller supports the AlaMode in version 3.3.8

I’ve fixed a problem with Grbl Controller where it expected Grbl to reset upon serial port open – some devices like the AlaMode initialize once and when you connect, there is no version response. The fix involved sending a Ctrl-X if no response was detected.

The AlaMode is an Arduino-compatible board that stacks on top of the Raspberry Pi and communicates serially through the GPIO bus.

Checkout my writeup on getting the AlaMode running with Grbl

You can pick one up at MakerShed

Shapeoko modified with belts on the outside

I’ve managed to upgrade my Shapeoko with belts on the outside. This gives me more working width and also moves the belts further away from debris. I ran a test and it works really well. I need to add a clamp down system, the pressure clamp approach mostly works but I have had one problem with it when a cutout piece moved while I had stepped away and popped the Lexan piece up in the air. Otherwise, the milling performance has been excellent so far into hard plastics (no problem with HDPE).

For the belt mountings, I used steel used for home construction (“Strong Tie”) and cut it into four pieces, then drilled it using measured templates. I did have to use longer 5 mm bolts because of the extra thickness of the plates.

It will make my limit switch mounting trickier, as my limit switch mounting holes were used to mount the steppers on the outside.

I am using thick Lexan for my stepper mounts and it works really well. The four holes in the corners are tapped for 5 mm bolts.

I reused the old Dremel mounting spacers for the stepper spacing mounts and also used extra parts that came with my second Y stepper kit from Inventables to complete the mounting.

All metal from the original Shapeoko kit is unaltered – nothing has been drillled, everything is either stock or has been bolted on (except for a couple of bolts I cut to shorten them).

stepper-mount zip file containing nc and cb files.

Replacement bed for Shapeoko

I finally decided to pull out the big tools and make a new bed for my Shapeoko. This build is inspired by this project:

http://www.shapeoko.com/forum/viewtopic.php?f=11&t=274

I glued two scrap pieces of 1/2″ MDF board together and then routered clamping channels.

The clamp material is solid 3/8″ aluminum rod cut to about 1 1/2″, drilled and tapped for 1/4″ bolts.

To see how well it worked with the DW660, I decided to try milling a scrap piece of 8mm Lexan I pulled from some equipment to make two stepper mounts for my next modification: the outside belts.

This time I’m getting proper “snow”. When I tried this with the slower Dremel I was getting hot flakes permanently adhering to everything on the machine. This time, no adhesion!

I was using a two-flute bit. Probably should have used my 4 flute instead as the final result wasn’t as good as I had hoped. Still not bad. Job run time was about 30 minutes. Could have be 20 minutes if I hadn’t decided to do the full mill on the two big circles and instead chosen a simple cutout approach.

Shapeoko now has the powerful Dewalt DW660 trim router as a spindle

I ordered the DW660 from Amazon and designed some brackets in CamBam, then milled them using my Dremel spindle. I’ve mounted the new spindle and have tried it with HDPE (cutting board). Works exceptionally well – no slowdown at normal speeds – speeds that would slow down the Dremel at least by half its RPM.

Check out my posting on the Shapeoko which includes gcode files for the brackets: http://www.shapeoko.com/forum/viewtopic.php?f=8&t=1346

I’m currently working getting a proper clamp-down system on the bed. Additionally, I’m working on a light sensor-based limit switch using milled holders. Hope to get that build report up on the web site soon.

Shapeoko reconfigured with dual Y drives

I’ve managed to get my Shapeoko working with dual Y servos – why? I was getting tired of the undriven side sloshing around whenever I tried to work harder material. I ordered the extra drive kit from Inventables – it came with some extra hardware that I didn’t need and was missing a part (which i found a substitute for in my parts bin), but overall happy with the purchase.

Since the stepper they provided was not matched to the ones I ordered (I had purchased the mechanical kit only and sourced my own steppers), I repositioned the existing stepper and made the new one the Z-axis. Only issue is that the voltage setting on the Pololu driver isn’t right – the stepper runs a little warmer than I’d like. I need to tweak the pot slightly to bring down the current.

Check out the swapped red/blue wires on the A axis (upper right) so the stepper runs in reverse.

Hoping to do a more extensive writeup of the transformation.

Side note: I tried to run the 6×6 inch calibration pattern (ShapeOko_Calibration_Pattern_01b.nc), but it doesn’t fit into my Shapeoko’s working area – it is about 1/4 inch too small. Will need to edit the original design and try again.

Nightmare on Lexan

So I tried to mill some 1/4″ Lexan (Plexiglas) and had the feed rate a little too high. After running for a few seconds with chips flying all of a sudden the V-wheels and assembly of the Shapeoko started making these thumping noises.

Turns out that the Lexan chips that were thrown about were molten and landed on the Makerslide V’s and froze there, adding “speed bumps to the road”, as it were.

After carefully scraping off the Lexan chips with my fingernails, it runs like new.

Next: Add small vacuum hose on the spindle to prevent this in the future.