Plate to support the Heated PCB? The kit I just acquired seems to assume that you'll supprt the heated PCB just on the corners and then rest the aluminum print plate on top of the PCB. I have a MK2a and the small holes at the 4 corners seem fragile to be the sole support for the print surface, but that's what seems to be shown on this page about the heated PCB's: [reprap.org] . It shows standoffs holding up the PCB with a piece of glass on top. I've seen others which have MDF or aluminum plates for supports to the PCB's and this seems like a good idea to me so I was planning on adding something like this, but wasn't exactly sure of mounting. The kit came with a plate that's the same size as the PCB which was intended for the Y-base plate (which limits the Y travel far too much because it's too wide). I was thinking to use this as the support for the PCB and then use a smaller plate for the Y-base to increase the Y range. I'll probably convert to only 3 supprt points between the base and the support plate to make leveling the bed easier but I'll have to work out all the details. (also need a hole in the middle for the thermistor.) Does this sound reasonable? I've heard of people putting heat reflecting insulation between the PCB and the support plate. Is this recommended? What type? Thanks for your help as a newbie. -Bret https://reprap.org/forum/read.php?1,188707,188707#msg-188707 Sun, 12 Jul 2026 07:48:46 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,188707,189564#msg-189564 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189564#msg-189564 ttsalo General Mon, 04 Mar 2013 13:39:28 -0500 https://reprap.org/forum/read.php?1,188707,189549#msg-189549 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189549#msg-189549
I was also considering finding some insulation that they use under the carpets in cars. It should be pretty thin and I assume flame resistant. Any other ides?]]> cobrageek General Mon, 04 Mar 2013 12:30:06 -0500 https://reprap.org/forum/read.php?1,188707,189425#msg-189425 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189425#msg-189425 waitaki General Mon, 04 Mar 2013 05:16:14 -0500 https://reprap.org/forum/read.php?1,188707,189342#msg-189342 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189342#msg-189342 wikipedia, sheep wool is naturally flame retardant unless mixed with some polyester which can make it flammable.]]> brnrd General Sun, 03 Mar 2013 19:44:41 -0500 https://reprap.org/forum/read.php?1,188707,189340#msg-189340 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189340#msg-189340
If you don't have springs, do you just use a nut to hold the bottom of the PCB and then lock them at the right hight to do the leveling? So it's positioned just the same but doesn't have the springy-ness? Maybe the springs just needed to be stronger or more compressed to avoid the bouncing on the other models as it seems like a very tight spring would provide the same stability as if they were locked in place.

About the wool, it was the strongest recommendation on the main heated bed page ( [reprap.org] ): "Commonly used insulator materials are cardboard, wool, and cotton cloth on top of medium density fiberboard MDF. Wool may be a good option for insulation because its ignition temperature is 600C". If what you say is true, we should probably fix this page so it isn't the recommendation.

Spk64, thanks for the picture. That really helps me understand the setup. I like that it reduces the number of pieces to make up the bed as opposed to going underneath the frame with the Y-rods and needing another plate in the system. Is that just aluminum foil wrapped around the cardboard? What is your experience with the springs?

Thanks for the tips.
Bret]]> cobrageek General Sun, 03 Mar 2013 19:17:05 -0500 https://reprap.org/forum/read.php?1,188707,189218#msg-189218 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189218#msg-189218 Lower plate Lexan bolted to Y carriage.
PCB bolted with risers to Lexan just enough space for 1 thickness cardboard wrapped in aluminum foil.
Glass plate clipped to PCB

No springs anywhere tried that for a short period and found out how bad it was.
Have not had to level my bed since assembly, still nice and flat nd level.
Lower Lexan just gets slightly warm , been running non-stop all weekend.
Have not had any issues with only using the 4 corners to support the PCB.

I have heard others using an aluminum plate on top the PCB to help spread the heat and extend the build surface slightly.

]]> Spk64 General Sun, 03 Mar 2013 11:28:48 -0500 https://reprap.org/forum/read.php?1,188707,189208#msg-189208 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189208#msg-189208
Read the blog from Josef Prusa dated 11/11/2001 here on the design of Prusa2 (Iteration 2). I'm guessing that there might be some confusion between the original Prusa and iteration 2 instructions.

Here's a good way to increase your z build height: [www.robosprout.com]

Also, it seems that wool is considered self combustible and highly flammable. Note that the bed is not going to be heated to no higher than 130C so cardboard is perfectly fine.]]> brnrd General Sun, 03 Mar 2013 11:10:06 -0500 https://reprap.org/forum/read.php?1,188707,189197#msg-189197 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189197#msg-189197 reprap.org] ).

brnrd, the kit is indeed a Prusa2 came with the frame mostly put together and it did have the Y bars below the frame and the print bed plate there which was limiting the Y-travel. I'd seen some instructions which have the Y bars above the frame as you indicate and that would improve the Y-travel, but the print bed ends up being higher which limit's the Z-range.

Then I discovered that on the main Prusa2 build page it shows the Y-bars below the frame but the key is that the Y-base plate they show is only 140mm deep. I measured it out and this provides enough travel that you can cover the whole print bed so it should be the same as if I put the bars on top. The trick is that I need to then suspend the main print bed (MDF board) at points above this smaller base plate. This is exactly what they do on the reprappro model ( [reprap.org] ). I think this ends up providing more Z-range as well as the maximum Y-range. The only possible issue is that the suspension points for the print bed are closer together rather than all the way at the corners, but I don't think that should be a problem (and seems to work OK for the reprappro).

Did I miss something in my figuring?
Thanks,
Bret]]> cobrageek General Sun, 03 Mar 2013 10:09:13 -0500 https://reprap.org/forum/read.php?1,188707,189083#msg-189083 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189083#msg-189083 waitaki General Sun, 03 Mar 2013 04:07:52 -0500 https://reprap.org/forum/read.php?1,188707,189043#msg-189043 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189043#msg-189043 xclusive585 General Sat, 02 Mar 2013 22:08:27 -0500 https://reprap.org/forum/read.php?1,188707,189039#msg-189039 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189039#msg-189039
Also, you have to put some air or insulation and air between the mdf plate and the pcb heated bed. A cheap insulation is a sheet of corrugated cardboard. For a spacer, you can simply use M3 screws and nuts.]]> brnrd General Sat, 02 Mar 2013 21:18:20 -0500 https://reprap.org/forum/read.php?1,188707,189036#msg-189036 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189036#msg-189036
Thanks,
Bret]]> cobrageek General Sat, 02 Mar 2013 21:07:14 -0500 https://reprap.org/forum/read.php?1,188707,189022#msg-189022 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,189022#msg-189022 waitaki General Sat, 02 Mar 2013 18:46:28 -0500 https://reprap.org/forum/read.php?1,188707,188845#msg-188845 Re: Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,188845#msg-188845 Thanks,
Bret]]> cobrageek General Sat, 02 Mar 2013 01:01:54 -0500 https://reprap.org/forum/read.php?1,188707,188707#msg-188707 Plate to support the Heated PCB? https://reprap.org/forum/read.php?1,188707,188707#msg-188707 reprap.org] . It shows standoffs holding up the PCB with a piece of glass on top.

I've seen others which have MDF or aluminum plates for supports to the PCB's and this seems like a good idea to me so I was planning on adding something like this, but wasn't exactly sure of mounting. The kit came with a plate that's the same size as the PCB which was intended for the Y-base plate (which limits the Y travel far too much because it's too wide). I was thinking to use this as the support for the PCB and then use a smaller plate for the Y-base to increase the Y range. I'll probably convert to only 3 supprt points between the base and the support plate to make leveling the bed easier but I'll have to work out all the details. (also need a hole in the middle for the thermistor.)

Does this sound reasonable?
I've heard of people putting heat reflecting insulation between the PCB and the support plate. Is this recommended? What type?

Thanks for your help as a newbie.
-Bret]]> cobrageek General Fri, 01 Mar 2013 11:02:52 -0500