Yet another cast aluminum plate topic...

TLeTourneau

I'm thinking about moving to a cast aluminium plate, I'm stuck on what thickness to get. The plate would be 500x500mm (19.6875"2 square) and the options seem to be 5/16" or 3/8", 1/4" was deemed to be to thin for that size in another thread. The 3/8" weighs 14 Lbs and the 5/16" weighs 12.2 Lbs and costs $10 more. I'm just not sure which way to go, I don't know if the additional 1.8 Lbs makes that big of a difference. I am also planning on rebuilding the bed frame with 2020 or aluminum angle to increase stiffness if needed. I'm not against changing the Z axis motors to NEMA 23's either. Any thoughts or advice would be truly appreciated!

My machine is a CoreXY with dual Z axis using single start T8 leadscrews that have a 2mm lead. On the plus side I live about 90 minutes away from Midwest Metal Supply.

deckingman

@tletourneau This is one of those questions where you will likely get dozens of recommendations. I'll start the ball rolling.

I chose 10mm (3/8") thick for my 400mm x 400mm bed but if I did it again I'd go for 8mm (5/16") because it takes a tad longer than I'd like for the heat to "permeate" through to the top surface (I use a mains powered silicone heater). However for 500mm x 500mm, I'm not sure.........hmm..... on balance, I'd probable go for 8mm (5/16) well supported on a 2020 frame.

Oh, BTW I use a single Nema17 with 3 off 1mm lead screws and a continuous belt. You don't say how many motors you are using but if it's multiple - then (high torque) Nema 17s will be fine IMO.

TLeTourneau

@deckingman thanks for the reply! Finding an appropriate, reasonably priced, heater for a 500x500mm build plate has been another challenge. I have no problem going with a mains powered heater controlled by a SSR but finding one has been fun.

I have dual independent NEMA 17 60mm Z motors. I'm not sure of the torque rating as TronXY doesn't really publish the specs but the sticker on the motors say "SL 42STH60-1684A".

Surgikill

Where are you finding these plates and for what price? I'm looking for some.

TLeTourneau

@surgikill Midwest Steel and Aluminum Supply (https://www.midweststeelsupply.com/store/aluminumplate). For the size I'm looking at it's about $73.00 for 3/8" and $83.00 for 5/16" plus tax. Shipping would be additional, I'm somewhat local at about 90 minutes away so I would pick it up.

SupraGuy

Yeah, there will be lots of recommendations, and It Depends...

If you are willing to add supports, then the 5/16" should be fine. A good support structure will help keep things flat when heated.

Over 500mm, there will be some thermal expansion, so how you hold things together will matter. You will have to allow for the plate to expand and contract.

gtj0

My 500x500 MIC-6 is 1/4" and I've not had ANY issues with a minimum bed temp of 70C. My 3 point ball and slot mount allows the bed to expand/contract without any lateral movement.

dc42

@tletourneau said in Yet another cast aluminum plate topic...:

Finding an appropriate, reasonably priced, heater for a 500x500mm build plate has been another challenge. I have no problem going with a mains powered heater controlled by a SSR but finding one has been fun.

Both Keenovo and Shenzen Ali Brother Technology (via Ali Express) will make one to your size, voltage and power specifications.

TLeTourneau

@gtj0 thanks! I'm looking at 100-110C (I print a bit of ABS) that's one of the reasons I am thinking a bit thicker may help. I'm not overly concerned with the heat up time but rather the weight, especially after I put a 1/4" thick piece of glass on it.

TLeTourneau

@dc42 thanks for the reply! I should have been more clear, I apologize. I know there are options I can get from China, I'm trying to find a US supplier to cut down on shipping time. I wonder if a heater designed for a CR-10 S5 would be ok?

gtj0

@tletourneau said in Yet another cast aluminum plate topic...:

@dc42 thanks for the reply! I should have been more clear, I apologize. I know there are options I can get from China, I'm trying to find a US supplier to cut down on shipping time. I wonder if a heater designed for a CR-10 S5 would be ok?

I got mine from these guys...
https://www.ebay.com/usr/autonomousindustries?ul_noapp=true
120V 1600w
Ordered on Wednesday, had it the following Monday.

I don't see the 500x500 listed any more but you could ask them.

gtj0

@tletourneau said in Yet another cast aluminum plate topic...:

@gtj0 thanks! I'm looking at 100-110C (I print a bit of ABS) that's one of the reasons I am thinking a bit thicker may help. I'm not overly concerned with the heat up time but rather the weight, especially after I put a 1/4" thick piece of glass on it.

I also tried the tempered glass over aluminum route. It's going to be a bitch to get heat transfer from the aluminum to the glass unless you use a thermal adhesive or paste between them. I tried various things with the help of a Flir camera and gave up. In the end, I went with a Printbite surface and haven't looked back. If you do go with the glass, then the aluminum is really just for heat spreading and mounting so thinner is better.

dc42

@gtj0 said in Yet another cast aluminum plate topic...:

I also tried the tempered glass over aluminum route. It's going to be a bitch to get heat transfer from the aluminum to the glass unless you use a thermal adhesive or paste between them.

Also, tempered glass is frequently warped by the tempering process.

deckingman

@gtj0 said in Yet another cast aluminum plate topic...:

I also tried the tempered glass over aluminum route. It's going to be a bitch to get heat transfer from the aluminum to the glass unless you use a thermal adhesive or paste between them...............

As @dc42 said, tempering glass (or toughening it) causes is to distort - been there, done that, got the Tee shirt. So if you use glass, stick with plain non-toughened, float glass.

Heat transfer isn't a problem - if it was, I wouldn't need double glazing in my house I get 2.5 degree top between the top of my aluminium bed and the top of the 6mm glass at 55 deg C bed temperature. If that's critical, just set the bed 2.5 degrees warmer. Personally I just use a squirt of 3D lac then I can print pretty much any filament at any temperature over about 50 deg C so bed temperature doesn't really matter to me.

mrehorstdmd

If anyone lives in the Milwaukee or Minneapolis area, Howard Precision Metals sells MIC6 cutoffs for $1.50-2 per lb. My 300x300x8mm bed plate that started as 13.5" x 15" cost me $15 when picked up locally.

gtj0

@deckingman said in Yet another cast aluminum plate topic...:

@gtj0 said in Yet another cast aluminum plate topic...:

I also tried the tempered glass over aluminum route. It's going to be a bitch to get heat transfer from the aluminum to the glass unless you use a thermal adhesive or paste between them...............

As @dc42 said, tempering glass (or toughening it) causes is to distort - been there, done that, got the Tee shirt. So if you use glass, stick with plain non-toughened, float glass.

Heat transfer isn't a problem - if it was, I wouldn't need double glazing in my house I get 2.5 degree top between the top of my aluminium bed and the top of the 6mm glass at 55 deg C bed temperature. If that's critical, just set the bed 2.5 degrees warmer. Personally I just use a squirt of 3D lac then I can print pretty much any filament at any temperature over about 50 deg C so bed temperature doesn't really matter to me.

I'm just reporting what I saw with the Flir and I did try float glass as well. It took a long time to get an even distribution of heat to the surface. Actually, a little bit of mineral oil on the center of the aluminum plate before laying the glass on top made a huge difference. Anyway, moot point for me. The printbite directly on the aluminum has been working great.

TLeTourneau

My glass is NeoCeram fireplace glass that I got from a local shop. I use a .5mm layer of high temp silicone sheeting between the glass and the heat bed.

@mrehorstdmd - thanks for the pointer! I'll give them a call.

jrjones88

Here is another place that sells off cuts of cast aluminum, out of California: http://www.sandsmachine.com/alumweb.htm

mrehorstdmd

@tletourneau go to https://www.howardprecision.com/random-rack to select a piece, get a quote, and they'll send a confirmation email. Then you email back and then tell them you want it and will pick up and they'll get it ready for you.

TLeTourneau

@mrehorstdmd thanks again for the replies! I called and talked to them, nice people. They no longer have a facility in Minneapolis so no local pickup for me. They have a piece of MIC6 that was $40.00 and was $67.00 shipped. The issue was that it is 19 5/8" x 28" and I couldn't find anyone local to cut it to size. If I have Howard cut it the price goes to over $100.00 shipped. I was able to get a 19.675" square 3/8" piece of ATP5 for $95.55 shipped. I've ordered a SSR and some 184C thermal cutoff fuses. Now I just need to order a 120v silicone heat pad. Looking at the frame and thinking through it I think a slightly smaller than 500x500 would be a good idea to give me room to mount the bed to the frame, like 460x460 if I can find one in 110v.

I have also ordered enough 2020 extrusion to build a stable gantry for bed (along with MGN15 linear rails for the X and Y axis).