JD's Garage DIY CNC Plasma table build

[GG1]

My printer is in my workshop/garage and a couple of times when I opened the main garage door the draught/temperature drop caused a print to lift. I've built a simple enclosure out of scraps of hardboard/thin ply and it results in the temperature being approx 10°C above ambient without any extra heating. Also as your prints seem to be taking a long time have you tried a larger nozzle? A 0.8mm nozzle makes printing a fair bit quicker.

Yes they are very slow - reducing the speed down to 30 mm/s was the only way I found printing PETG reliably. Also using 0.2mm layer height, which I know isn't needed.

I haven't ever considered a 0.8 nozzle but rereading JD's Garage's document it is what they use for their commercial prints.

 

[GG1]

II have not done this personally. I just copied this of a forum as it might help you...


"I have done this with Cura a few times. Take a look at the plugins that come with Cura (I’m looking at version 19.12). It comes with two plugins: Pause at height and Tweak at Z. Tweak lets you change speed, temperature, flow rate and fan speed. Pause lets you move the head to a location (so you can change filament) and then will resume where it left off.

Very handy."

Yes that is very helpful, thanks!

 

[GG1]

I normally print PETG at 250, but exact temp depends on the printer.
Given the size of prints, it's probably worth printing some temperature towers to find what gives the best finish.

It might also be worth turning off part cooling, as on large parts it's not as critical.

I did some temp testing and 245 on my printer seemed to be the sweet spot, but that was in a nice warm room without a breeze. I'll cut the fan as you suggest.

 

[iNf]

These are the nozzles I bought

iMetrx MK8 Nozzle 3D Printer Nozzle Cleaning Kit (34Pcs/pack) for Ender 3 nozzle, Ender 3 v2 Nozzle Brass Nozzle0.2mm 0.3mm 0.4mm 0.6mm 0.8mm 1.0mm Stainless Nozzle 0.4mm https://amzn.eu/d/gmFfnYQ

 

[ukracer]

These are the nozzles I bought

iMetrx MK8 Nozzle 3D Printer Nozzle Cleaning Kit (34Pcs/pack) for Ender 3 nozzle, Ender 3 v2 Nozzle Brass Nozzle0.2mm 0.3mm 0.4mm 0.6mm 0.8mm 1.0mm Stainless Nozzle 0.4mm https://amzn.eu/d/gmFfnYQ

I can't load the page!

 

[iNf]

Oops neither can I

https://amzn.eu/d/24rywuh

Try this link
If you copy and paste the long one above it should also work

 

[fizzy]

This morning's effort brought to you by Brillo.

Interesting failure, the first flat section printed fine, but the upright part of the L section curled up. It has been colder and windy here - I don't trust the printer running overnight so have it in the back corner of an outbuilding on the concrete floor, but I think there is a cool breeze getting to it.

View attachment 418576 View attachment 418577

Thicker first few layers and bigger brim.
Very interesting project will watch with interest!

 

[GG1]

On to cutting out some 5mm steel for the Y Axis connecting plates.

They helpfully provide 1:1 drawings to print and stick to the steel plate but the printer needs to be reasonably accurate so they also provide a calibration drawing in case you need to adjust.

Not something I had done before and in case anyone else needs to, here's what to do:

- don't use Adobe Reader or similar to print the .pdfs, I found that was miles out. Use Adobe Acrobat proper.

- print out the calibration drawing and measure one of the larger boxes, the one which should have been 102mm in my case

- Then do the calculation:

Drawing dimension / actual dimension x 100

in my case 102/101.49 x 100 = 100.5

- Use this number in the Print window for the Custom scale %

This seemed to get the print pretty much bang on. Overkill I'm sure in this case but a couple of the drawings are for the NEMA motor mounts so should be reasonably accurate I'd have thought.

 

[GG1]

Spray adhesive on the 5mm plate and I'm now wondering why I didn't decide to fix the bandsaw before taking on this project.

Just need to remember to centre pop the holes then have at it with the grinder and scary slitting disc.

 

[GG1]

A trip to the steel stockholder and after some cutting, grinding and drilling the dry fit is starting to look like a Y axis.

I've decided to go for a cuttable area of at least 1250x1250mm to get half a sheet on at a time - it's not quite clear from the drawings what size I need to make it so did some back of the envelope sums, added a bit and came up with the Y axis tube lengths of 2000mm which should give some room for error.

Hopefully I'll get the Y axis motor mounting plate and belt anchors completed over the weekend ready for the arrival of the stepper, driver and belt on Monday.

 

[knighty]

I'm very interested in this too, eager to see how it turns out :-)

 

[GG1]

A bit more metalwork and the Y Motor mount plate is on. All straightforward as per the instructions.

That's not the motor which will be used, just one of the same frame size to check for clearance. The real one arrives tomorrow when hopefully parts will be painted and ready for mounting the motor along with the belts and gears.

I think that once that's complete I'll start playing with the electronics and software to get things running in principle before adding the X axis, legs etc. which will take up a lot more room in the workshop.

 

[GG1]

A little progress to report during the week.

Firstly, how to finish the rails - he main thing I'm after is corrosion protection and while I've seen some people paint, the bearings wear off stripes which doesn't look great. So I decided to cold blue hoping it will stay there longer.

Before and after....hmmm

I did what I always do when cold blueing and expected different results, wonder if there's a word for that. It does look a bit darker in real life though.

 

[GG1]

When assembling the motor mounting plate and belt runners I realised that the tappings weren't perpendicular to the plate which would have no doubt caused issues with the belt trying to track. Just can't get the staff these days.

So I drilled out the threads and welded nuts on the back instead, I love the smell of zinc in the morning. Holding in place with the bolts and washers to ensure they are square this time. Luckily there is clearance on the back side for the captive and jam nuts.

 

[GG1]

All back together and the full Y axis including belt and mounts is now complete....

 

[GG1]

...sort of, not happy with the 3D printed belt anchors.

JD's garage do say they are just an option and also include drawings for metal brackets, which is today's job. The plastic ones just don't feel right for the job and will be begging to be knocked off at some point, sitting as there are right on the corners.

 

[Baloo]

l will follow along as l just bought the same plans last week, printing them out today, be good to see how someone else has tackled the biuld
Andy

 

[GG1]

She's alive!

 

[GG1]

Excuse the sketchy setup but I took a quick break from the fabrication to see it move and had a quick art farse with a clock on it.

It honestly took less than 30 minutes to download and configure the software, programme the Arduino, wire it up and get it moving. That on its own was worth buying the plans - there's nothing proprietary, the software is all open source and there are numerous different ways of doing it shown on the internet, but it was just all spelt out in the pack of info they supply and life's too short to find it all out for myself.

The axis is much longer than the design specifies, and I have no idea what the tension on the belt should be, but impressively accurate I thought with around 0.05mm of backlash - on something where probably 0.5mm tolerance would probably be fine for me.

 

[GG1]

l will follow along as l just bought the same plans last week, printing them out today, be good to see how someone else has tackled the biuld
Andy

Good luck, drop me a line if you get stuck although more likely it'll be the other way round.