Core-XY based on Rat Rig V-Core and Duet 2 Ethernet

snoozer

More parts have arrived.......

My temporary solution for the heated bed, a adhesive 24V silicon heater pad, inductive proximity switch, end stops with roller levers and the spring steel sheet with adhesive PEI.

The bed heating and print surface are temporary items just to start doing things. The goal remains to be a mains heated 1.1kW bed from E3D. I have not yet found a final solution for a print surface, so I am still on the look out for a factory coated spring steel sheet with PEI. I am also looking at a Piezo based Z-Probe, I may get hold of a alpha version from someone Tom's 3D printer forum, if that should work I may also consider a glass print surface but I have never printed on glass, so that's another experiment.

The tubing is to guide the filament from the spool holder to the hotend, it is direct drive but I prefer the spool holder detached from the printer to avoid large masses amplifying potential resonances in the printers mechanic on quick moves. I have had a spool holder on my Prusa printer attached to the frame which caused a lot of movement.

Jan

snoozer

Before ppl mention it, no I very much dislike the location of the termistor, this was not clear to me before I ordered. I had preferred it to be near the middle of the heater. I do like the fact the cables are in a silicone tubing.

Jan

deckingman

@snoozer said in Core-XY based on Rat Rig V-Core and Duet 2 Ethernet:

Before ppl mention it, no I very much dislike the location of the termistor, this was not clear to me before I ordered. I had preferred it to be near the middle of the heater. I do like the fact the cables are in a silicone tubing.

Jan

Depending on how thick the aluminium bed is, then having a thermistor close to the heating element is really bad idea. The reason is that it takes a certain amount of time for the heat to find it's way to the top surface of the plate. So what happens is, when the heater comes on, the thermistor "sees" the rise in temperature at the heating element so the firmware turns the heater off (or more precisely adjusts the PWM value if you aen't using "bang bang" mode). Then it waits a short time for the temperature to drop, then starts heating again but it very rapidly reaches a high temperature at the heater to plate interface so the heater turns off and the cycle repeats. The net result is that it takes a very long time for the upper surface of the build plate to reach the required temperature. What I did with my thick aluminium plate was to drill a small hole in the edge, close to the top surface and as deep as I could, the fitted the temperature sensor onto that hole.

snoozer

@deckingman

That sounds very plausible, if I was intending to use that set-up in the long run I would consider that suggestion. IDK for sure how E3D has done that, the documentation and spec sheet does not give away a lot of detailed info. I would just assume they know what they are doing. I am however still pondering over another issue. Making it magnetic for a spring steel sheet. I was thinking to machine little round holes in the bottom to maybe 0.3 mm below the top surface to add magnets from below the alumimium plate. Would the aluminium prevent the magnetism to work ? Sure on the E3D heater that would not work at all since the heater is fixed by the factory. An adhesive magnetic surface is really not what I think is the good way to go, then I'd rather use fixing clips at the edges I guess. Another idea was to have 2-3 index pins on the heated bed and corresponding precise holes in the print surface so there can be no lateral movement of the print surface but would that be bad for heat conductivity if there is only the weight of the print surface to make contact between bed and surface........ The print bed is for me personally the biggest challenge to figure out yet.

Jan

PS: Looking at the E3D assembly guide it looks as if the termistor is at least in the middle, if its in a machined groove or hole is not really clear to see.

https://e3d-online.dozuki.com/Guide/High+temperature+bed+assembly+guide./80?lang=en

deckingman

@snoozer I don't know what E3d's heated bed is made of but from the pictures in the link you supplied, it doesn't look very thick. In which case, I doubt that there would be much of a problem with heat transfer from the underside to the top side. Quite how flat that heated bed would be is another matter.

I just kind of assumed that you would use something like 8mm thick aluminium tooling plate for you bed. I chose 10mm thick but in hind site, 8mm would have sufficient.

I've just noticed that in the RatRig kit you get a 3mm thick aluminium heat spreader. Personally, I'd simply throw that away....

snoozer

@deckingman

You are probably right with that, I have no experience with building my own yet. Nothing is set in stone for me only that is has to be Core-XY and I want to use the Duet 2. So you are using an adhesive heat pad ? Can that go to 110-120 degree c without issues ? E3D is recommending a glass surface, that should be level enough as long as there is no excessive force applied. True, that does not really give me any assurance regarding my spring steel sheet idea.

Jan P.

snoozer

I had a look around for adhesive silicone heaters, in the usual places for 3D printers they don't show much actual tech specs and they seem rather cheap. If I look at RS Components for example they state continuous operating temperatures of 150-200 degree c. Is that realistic ? At RS they are around the 130-180 euro mark for heaters approx 300x300 or the imperial counterpart. The adhesive part would be the most worrying to me. Will it be durable or peel away from the aluminium plate......

Jan

deckingman

@snoozer I bought my heater from AliExpress. I can't off hand remember the seller, it might have been this one https://www.aliexpress.com/item/1400w-240V-400-x-400mm-Silicone-Heater-Bed-Heating-Pad-for-3D-Printer-Without-Hole-Office/32880041524.html. They will make any size, any voltage, any wattage. I know it's from China and like most of us, you might have reservations - I did initially. All I can say is that it has worked flawlessly for the past 3 to 4years.

As I said, I use flat, aluminium tooling plate, 10mm thick) although 8mm thick would be fine. The heater is stuck to the underside and I use two layers of semi-rigid insulation under that. I use 6mm thick glass on top because it is flat, cheap, and I like having a removable print surface so that as soon as one print is finished, I can start another without waiting for the bed to cool.

I use 3 lead screws, one near the each corner at the forint and one in the centre at the back. These are driven with a single motor via a continuous belt. Initial levelling is done by slackening the pulleys on the lead screws and adjusting each one. Subsequent levelling isn't needed. The bed is flat and level and stays that way.

I don't use any form of bed level or flatness compensation and I can do things like this https://www.youtube.com/watch?v=U733PMTou7M.

That's an old video - these days I use 3DLac on my glass which allows me print the first layer very much faster. In fact, I don't slow the speed down at all for the first layer so typically lay it down at 90mm/sec. Oh and I can also do things like this which requires very good bed adhesion https://www.youtube.com/watch?v=vG1WqijJ634

snoozer

@deckingman

Oh that's very nice. Did you machine your bed yourself or did you use Weerg or such ? I have never printed on glass, on the Prusa I can't try it cause it has an inductive probe and I don't want to start ripping things apart to do manual bed leveling. I will add that to my list to things to check out for the cost of getting a decent strong print bed machined. A continuous belt on the Z would not bother me to much. As long as the absolute position is correct after the move any flex should not matter. A three point mounting is understandably the best if the structure does allow for it.

I check that out regarding a custom print bed......

Jan

deckingman

@snoozer
I bought aluminium tooling plate cut to size from a UK supplier.

Personally I like printing on glass. Others hate the idea - mostly people who have never tried it. But it doesn't have to be glass. What I like most is the ability to quickly remove one piece at the end of a print, slide in another piece and resume the next print quickly. Any removable build surface would do as long as it's flat. Glass happens to fit the bill, being relatively cheap but flat and 6mm thick is surprisingly difficult to break. I have 3 pieces and of course, you can use PEI, or 3D Lac or blue painters tape on each one and swap between them.

One word of caution - do not be tempted to have the glass toughened. The toughening process will distort it so stick with plain float glass. That was a lesson I learned the hard way.

Edit. I did sort of machine the plate. But only drilling the fixing holes and then counter sinking them. It did it all with a hand held power drill - nothing special. Initially, I did mill a slot using a wood working router, on the underside of the plate to take the thermistor but later abandoned that in idea in favour of drilling a hole in the side.

snoozer

@deckingman

I have flicked through some of your YT videos. Man what a machine !!!! The dynamic counter weight is absolutely stunningly well done and is works so well.

I am beginning to seriously consider a chunky aluminium plate with adhesive silicone heater mat. I'd still go for main 230V powered cause i hate low voltage high current stuff, just does not sit well with me. I have just bough a reasonably decent but not to expensive router to be able to make the ends of the aluminum extrusions of the V-Core true and equal length assuming they are not machined properly. I suppose that could also work to cut a slot in the aluminium plate for the termistor and make it true and nice around the edge. I did a quick and non to elaborate aluminium plate in fusion 360 to upload to Weerg for a quote. It had 3 mounting slots 4.2 mm width and a slot to the middle for termistor. Weerg will not accept it for quoting cause the ratio of thickness to outside circumference on the 320x320x8mm plate is to much for them. I have the option for a manual quote but I leave that till I have a final design. The heater I have narrowed down to on a quick search is this:

https://ie.rs-online.com/web/p/silicone-heater-mats/1065429/

It is rated 150 degree c continuous operation and my experience with RS is 99% positive. I keep an open mind, once the V-Core kit arrives I have a better idea what may and may not work mechanically on that kit.

Thanks for your suggestions and shared experience !!
Jan

PS: The quote from the Weerg website is

"The morphology of the piece does not allow a safe realization.
We do not execute objects whose perimeter exceeds100 times the height (now it's170.0 times).
The reason is due to the fact that vibrations could reduce the workpiece precision during the machining process.
Do you think the piece can be made?
Do not hesitate to contact us, by clicking here."

deckingman

@snoozer That's a weird thing for Weerg to say IMO. The piece of tooling plate I bought is 400mm x 400mm which therefore has a perimeter of 1,600 mm. By their reckoning, it should be at least 16mm thick which I'd say is a bit crazy.

Ref RS, yes I have an account with them. Yes they are good and delivery is fast but soooo expensive. 178 Euros !!. Suggest you shop around.

Edit. Keenovo have a good reputation - worth checking them out https://www.keenovo.com/products/silicone-heater.html

snoozer

Uups..... just got quoted 515 EUR for the bed plate 320x320x8 with the milled slot for the termistor, 3 mounting slots 4.2x14 and rounded edges....... definitely NOT going for that. This was with Protolabs. I keep looking, there is no rush.

Jan

Veti

https://clever3d.de/epages/7a4290fc-7c7f-46cc-9b99-eadef22228e2.sf/de_DE/?ObjectPath=/Shops/7a4290fc-7c7f-46cc-9b99-eadef22228e2/Products/c3d-DP/SubProducts/c3d-DP-0039

328x328x8 for 63,75 €

snoozer

@veti

Oh wow, that looks promising !! I keep that on my link list for supplies. Thanks for sharing !!!

Jan

PS: Nice online shop, A lot of stuff I had spend days looking for and could not find. I never search in German on google, maybe that's why this never came up.

Veti

the site says since they manufacture each plate individualy they can make it to your likeing. so 320x320x8 should also work

snoozer

@veti

I have seen that, the 320x320 is just a figure out of my head, I have to wait till the V-Core kit has arrived to see exactly how big I can make it. But definitely a good place to check out. Also they do laser cutting, good to keep that in mind for the enclosure at the end of this project.

Jan

Dougal1957

I got my tooling plate from Ecocast tooling plate not to bad on pricing and very quick (Carriage is the killer but get manageable if you want a lot of stuff as it is a fixed rate)

If you want it customised to a specific shape etc then I would suggest getting it water jet cut so as to not induce any real temp change which may just shock it to warp although I think that is unlikely to happen but you never know.

My Silicon Heater is from Keenovo and I can say they are the best of the chinese makers having had several of them now. they will make it with holes in them wherever you want them ie for mounting holes and in my case I have a 10 mm hole in the centre of them that way I can drill a 3mm hole that doesn't quite go thru the ally bed and then I glue in a temp sensor using Arctic Silver thermal epoxy.

HTH

Doug

snoozer

@dougal1957

Also added to my link list. deckingman also recommended the Keenovo heaters, I have looked at them and they do a great variety of them, the price is very good (Customs or at least VAT will be added on arrival). My main concern is the adhesive, but it must be good otherwise it was not recommended I guess.

Jan

deckingman

@snoozer said in Core-XY based on Rat Rig V-Core and Duet 2 Ethernet:

@deckingman

I have flicked through some of your YT videos. Man what a machine !!!! The dynamic counter weight is absolutely stunningly well done and is works so well.

Thanks for the complement. Don't get too excited about the dynamic load balancing though. Although it does a good job of stabilising the printer as a whole, there is no improvement in print quality. That's because the frame is very stiff so although the entire printer rocks about, everything rocks together so there is no adverse effect on print quality to start with. It's a solution to a problem that doesn't exist on my printer and I was stupid in not evaluating that at first. But I always share my experiences, both good and bad, on my blog as it might help others. So, if you have a stiff frame, don't bother trying to cancel out the forces. If you have a frame that can "flex" and you get problems with prints because of that, then this might be worth a try.