Looking to make a custom sized heated build pcb - help??

Ok, im increasing the build area size of my prusa I3 - actually redesigned but well cover that later.
In any case I want to take advantage of the build area better. right now im wasting about 6 inches in width.
So Im looking to make a pcb that will cover 13" (x) by 9-10" (y).
Anyone know where I can get a HBP that size or figure out how to design an etching myself?
Thanks!
Jeff

Im also interested, although in a larger format, 500mmx500mm. also does anyone know where to get that big of a pcb? and if someone can do it for cheap?

Same, interested, for a 300mm x 300mm (12" x 12") heatbed.

I thought about making a PCB with such process : [www.youtube.com] .

But first the need is to design the traces. How to do it accordingly the copper layer thickness ? What resistence goal and power need beside ?...

I think finding 300mm x 300mm copper clad board is gonna be a bit tricky, you might want to design a 150mm x 150mm board and place 4 of them on your bed. This would also make prototyping much cheaper. You could then have a big one made once you get your design right.

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A wise man once told me "Never trust a man who doesn't own a shed!"
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Gen 6 daughter board
[forums.reprap.org]
Mendel PCB heatbed
[forums.reprap.org]
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You're right. I saw 150 x 300 boards, I'm thinking about a 2 parts design.

Remember that power scales with the area... so if you want a 400x400mm heated bed, expect that it will take 4x as much power as a 200x200mm heated bed. You will have to plan your traces accordingly so that the current draw is appropriate for a given voltage.

Yeah, Ive designed and etched pcbs before, just not sure of the grid design or the resistance values needed to heat up enough and be safe.

try this [circuitcalculator.com]

Thanks for this link, looks interesting .

I would use a silicone rubber heater as they provide very even heating and are easier to find in larger sizes.

Eric

That's what is used for Lulzbot TAZ but it doesn't seem really satisfying.

Why?

Does it take too long to heat up? I am using 200W silicone rubber heat beds for my prusa i2s and they work great. They heat up way faster than the PCB heat bed and provide much more even heat. I mount them beneath a 4mm borosilicate sheet and I get excellent heat transfer.

Eric

Heres a 8.4 x12.6 "

[www.ebay.com]

You might as well switch to kapton + a heat spreader.

RP Iron Man Wrote:
-------------------------------------------------------
> I would use a silicone rubber heater as they
> provide very even heating and are easier to find
> in larger sizes.
>
> Eric

Agreed. Any larger than 8x8 (200mmx200mm) and you're going to run into issues with power draw and heat-up time. Some electronics aren't equipped to push more than about 10 amps at 12v, which would be a major problem for a larger board. That's why you typically see that bigger heated beds are driven by 24v DC or even AC.

If you replace the 11A PTC fuse on the RAMPS board with one rated at higher current, you can still manage to run the beds off 12V. This way you won't have to find a 24V Power supply. My silicone rubber heaters draw up to 17A without issues. Originally I tried a 350W heater but I had problems with the power solder joints oxidizing so I wouldn't recommend more than 20A. 24V is definitely the way to go though.

Eric

I noticed many reports of users having problems with their TAZ heatbed, that makes me think there are some reliability issues. Yet I don't have any idea about the rate of TAZ heatbed with issues versus those without.

If I well understood a main issue is the temperature distribution on the plate.
Here's the study Lulzbot is sharing working on a new solution for next batch : [devel.lulzbot.com] .

Kapton circuit solution remains a prototype one far too expensive for me now.

How would you identify a 12"x12" silicon heater as a good one for our application ?



RP Iron Man Wrote:
-------------------------------------------------------
> Why?
>
> Does it take too long to heat up? I am using 200W
> silicone rubber heat beds for my prusa i2s and
> they work great. They heat up way faster than the
> PCB heat bed and provide much more even heat. I
> mount them beneath a 4mm borosilicate sheet and I
> get excellent heat transfer.
>
> Eric

Since I can get away with 200W for an 8"x8" heater, I would recommend 400W to 600W power for a 12"x12" heater at 24V so that the current draw is kept reasonable. The higher the power the better so get the maximum power heat pad that your PSU can handle. With a 200W 8"x8" heater, I can reach 140C+ (never tested the limit ) but I can only reasonably sustain 110C to 120C throughout the print. The bed also heats up really fast (up to 120C in about 5mins with cardboard insulator). If you are looking to print a lot of Polycarbonate or even Nylon, a higher power heat bed would be beneficial. One major problem with the RepRap electronics is that the heat beds are notoriously underpowered. Even if you can reach 120C on a Prusa PCB heater, it is not powerful enough to provide stable heating throughout the print. In addition, the resistance of the copper clad PCB Heaters is not as accurate. Before I started using Silicone Rubber Heaters, I had problems with my Prusa PCB dropping to 80C during the print!

If you can't find a suitable 12"x12" heater elsewhere (BTW QU-BD is sold out and their heaters are underpowered anyway) I can have some heaters custom made for you. I have a supplier for Silicone Rubber Heat Pads but I have to order a few of them to get a reasonable price. I you and a few other people on this thread are interested, I can make a small custom order from them (the shipping makes it very expensive unless you order at least 5 heaters). I could provide you with a custom 12"x12" heater for about $80 plus shipping (I live in Canada). The price of the heaters scales with size, not power so higher power heaters do not cost more. Also, I can order several different sizes/power according to everyone's need. Keep in mind though that a custom order will take a few weeks...I also have three large heat pads that I didn't end up using for a 10.5"x10.5" print area. The heaters are 270mm x 270mm x1.5mm and run on 24V. I have these heaters with power ratings of 400W, 500W, and 600W which is ideal if you want to sustain high bed temps for Poly/Nylon. I was going to build a large M90 with these but I haven't had time I also have sheet glass that is 270mm x 270mm x 2mm and 270mm x 270mm x3mm which would be perfect for these heat beds. Let me know if you are interested

Eric

Eric, I'm very interested in 12x12 heat beds. I could use one right now for a nylon capable printer I'm building for someone who needs it ASAP.

After that I will need one for myself, as I want to make a second identical machine.

BTW I'm located between Toronto and Montreal.

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Yvan

Singularity Machine

Hey Yvan, your 12"x12" Nylon printer sounds really interesting and I would really like to hear more about it What type of cartesian movement system are you using? Are you going to have a non-moving bed? 300mmx300mm bed would be quite heavy with a sheet of glass on top so the standard moving bed mendel design doesn't seem like the optimal set up as it may limit your acceleration/speed.

As for the 12"x12" (300mmx300mm) silicone rubber heaters I would definitely be willing to order some for you. If you need 2 custom heat beds, I can sell the two of them to you for 150 plus shipping. I live in Toronto (Kilometers away from you!) so shipping should be very quick and cheap by Canada Post. However, if you are the only one you wants a custom order of 2 heat beds then it will be expensive for me to get these manufactured so I would probably have to order a few extra to make it worthwhile. Unfortunately I don't really need any more heat beds so it would be great if a few more people were interested. If no one else responds in the next few days I would still be willing to order these for you to get your Nylon printer off the ground. Keep in mind that it will take about 2 to 3 weeks for me to receive these custom heaters after I order them, and another few days to ship them to you.

I can customize these exactly to your need. If you want a true printing area of 300mmx300mm then I would recommend 320mmx320mm to 340mmx340mm depending on what type of clips you are going to use to clamp your glass sheet to your bed (keep in mind that silicon rubber heat beds are flexible so you need to have a flat surface like glass on top). Since you are going to be printing Nylon I would say that a 24V 600W heat bed would be more than enough. Keep in mind that I have never used a bed as large as this so I am not sure of what the ideal power rating is, but based on my experience with smaller beds 600W seems like it would be easily be enough to reach very high bed temperatures. Anyway, check your PSU specs to determine how much power you can spare for the heat bed. Let me know the specs that you want for these heat beds.

If anyone else is interested please let me know as ordering just 2 heaters is rather expensive for me.

Eric

I could be interested in 3 12"x12", knowing I'm making 3 TAZ and for the moment I'm mainly working on the first one.
For the first one I already have a RUMBA for electronics and a 12vDC 20A 240W Power Supply. This machine would be for PLA printing essentialy, first, and I could always replace the power supply by a 24v, yet I don't know if RUMBA will deliver 24v for heatbed output.

I'm sorry still being hesitating bewteen two options for heatbed :
- aluminium plate / silicon rubber heater / glass (as standard TAZ)
- light wood plate / peltier modules / aluminium plate with kapton (hoping for a lighter combo and interested in the cool down possibility with peltier modules)

Do you have any idea about your 12"x12" rubber heater weight ? And about its use with a RUMBA ?

Hey Couby,

RepRap Discount designed the RUMBA board to be able to handle 24V. However, for some reason they did not change the original fuses that come with the RAMPS board The bed fuse is rated at 16V 11A... I got around this by simply replacing the bed fuse with a 32V 30A rated fuse from Digikey. These are expensive but they do the job. If you decide to order the heat beds from me I can ship one of these fuses together with your heat bed for an extra 6 bucks (it will save you from the minimum shipping fee for ordering from Digikey).

As for your heat bed options, I don't see why you need an aluminium plate for the silicone rubber heat bed if you are printing on glass. I cut a 6mm MDF y-carriage using my laser cutter and mount the silicone heat bed on top with a 4mm sheet of borosilicate glass on top of the silicone heat bed. MDF (or any plywood for that matter) has very low thermal conductivity and high temperature resistance so it is the perfect as a base for the heat bed. Also, Silicone Rubber heaters use Nichrome wire evenly distributed throughout the entire area so an aluminium plate is not necessary. In addition, the glass plate will provide a flat print surface so you do not have to worry about the flexibility of the Silicone Rubber heat bed. I simply sandwich the silicone heat bed between the MDF base and the Borosilicate glass print surface clamped with bulldog clips.

As for cooling, I think Peltier Modules are unnecessary trouble. I would recommend that you use Nophead's cooling set up for the M90. Buy/salvage a large, high CFM server cooling fan and mount it to your frame facing the bed. Connect the fan to one of the unused RAMPS pins and add a command at the end of the G-code to turn on the fan until the bed has cooled.

Based on the weight of my smaller beds, I estimate the weight of a 300mmx300mmx1.5mm thick bed to be about 300g but this weight is due to the thick silicone rubber insulation. I think I can get them manufactured as 1mm thick or 0.5mm thick which will really cut down on the weight.

Let me know what you think.

Eric

I think your answers are clear and convicing .

Noted for the RUMBA fuse. I'll have other questions about a RUMBA with a 24V power supply but maybe I'd better do it in another topic...

For the aluminium plate, the reason I thought doing with is simply because the TAZ is designed that way. Yet I was wondering about the bearing holder life time beneath this plate (PLA printed) in case working with high bed temperatures. That was the reason of wood thoughts in second option plus weight considerations...

Will try MDF / silicon heater / glass plate .
I never made plate with MDF till there, what thickness would you recommend for such use and size ?

So, I'm still interested in 3 pieces + 1 fuse for my first RUMBA .

Noted for the delay, no problem.

For the silicon heater thickness, maybe it could be interesting to get it at 1 mm to reduce a bit the weight.
I would be interested in 320x320 in order to have a real 300x300 print space (if fine for Yvan and eventually others).

Hey Couby, check out the three most recent pics on my Flickr here (I tried attaching them but you can only upload files less than 600kb! ) These pictures are of my modified Prusa set-up and illustrate the heated bed mounting.

I have implemented a 3 point leveling system that makes bed leveling soo much easier. I never understood the 4 point leveling system When you are adjusting 4 points in a plane adjusting one point affects the position of the others. As a result, bed leveling becomes an iterative process where you have to continue to adjust each point over and over again until your bed is sufficiently level. On the other hand, with the 3 point system you only have to adjust each point once (only 3 adjustments ) This makes sense as any 3 points in space will define a plane yet any 4 points may or may not define a plane. Anyway, I use 2 sheets of 6.5mm MDF connected by 3 bolts (with springs). The MDF sheets have pieces cut out (not solid) to save on weight while maintaining structural integrity. This design has many advantages: 3 point leveling, lightweight, sprung bed (safety for the nozzle crashing into the bed , bearing holders are completely thermally isolated from hot bed, and wing nuts allow for very easy 2 second bed leveling .

I print all of my printer's frame components in ABS so the bearing holder thermal isolation does not really make a difference for me but it would be useful for you if you have PLA parts. However, in the long run I think it is worth it to replace the PLA parts with ABS ones, here's why: As you noticed in the pictures, my printer is encased in a "garbage chamber" for printing ABS parts. With a thin clear garbage bag around my printer and the bed temp set to 90C the chamber temp reaches about 40C. If you wanted to print Nylon or Polycarbonate with higher bed temps and thicker clear garbage bag insulator, then you could probably reach up to 60C chamber temp...which happens to be above the glass transition temperature of PLA So any PLA parts within the high temp "garbage chamber" would start to get rubbery and generally wear quickly and fail I understand that people have a hard time printing ABS, but PLA really isn't suited for printer parts. BTW I have come up with a set up that completely (and reliably) eliminates ABS warping and results in much stronger parts but I don't want to go into details here as I think that would take us too far off topic. If anyone is still having problems with ABS let me know and I can start a new thread about this.

Anyway, back to the heat bed mounting. If you can't cut the two MDF plates yourself then I can cut them for you on my laser cutter as I can just barely cut MDF sheets to the size required for a 320mmx320mm bed. I could scale the same 3 point leveling design that I use for my Prusa printers. It would be lighter than using solid sheets. However, I would have to charge you 55 dollars as there are the material costs of 2 large MDF sheets and significant amounts of my time designing/cutting it If you are interested, all I would need would be a dimensioned CAD drawing or rough sketch of the position of the mounting holes for the bearing holders and y axis belt. I may not have time to do this for you but I can try if you are interested.

A 320mmx320mmx1mm thick silicone rubber heat bed sounds doable and if you need three and Yvan needs 2 then it should be enough for me to order from the manufacturer even though it is still a very small order. I will check with them to make sure. Also what power rating would you want for your heat bed? My estimate would be that 400W to 500W would easily be sufficient for ABS but if you want to maintain the bed at really high temps for Polycarbonate or Nylon then maybe 600W+ would be better (BTW all at 24V). These are all rough estimates but they shouldn't be too far off the mark.

Eric

Eric, I love your garbage chamber! LOL

My wife put a 3D line rendering of the nylon printer on the blog, and we might be able to take photos of the assembled frame tomorrow. It is boxed in with MDF and acrylic or polycarbonate windows for the heat chamber effect. I am not sure what temps I will need in the chamber for nylon, but I know that will reduce the wattage required for the heated bed. I have two motors that are inside the heated chamber so I have to see if I run into trouble above 40°C, their approx max temp rating I think.

I am still moving the heated bed/Y axis RepRap style but on 12 mm smooth rod instead of 8 mm. I will not get much speed, but that is a trade off with being able to build this machine without adding more layers of experimental design. I am allowing room for an upgrade to NEMA 23s for the Y and X axis if needed. I might buy the Eckertech RAMPS package with the higher power stepper drivers for that, just in case.

For me it is not critical to have exactly 12 x 12 inches of printable area. There is also a heated bed temp drop off issue around the perimeter so 12 x 12 is theoretical if the edges are several degrees cooler, which they will be. That is where the delamination will occur, so who knows right now what the real working area will be? Personally I would play it conservatively. The bigger the silicon heater, the higher the probability of failure due to higher power requirments, build platform mass and so on. If I could buy just one silicon heater that would be perfect. I want to try all options at this point.

So who else needs a 12 x 12 inch heater?

Now is it just me, or have we totally hijacked Parabolic's original thread??

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Yvan

Singularity Machine

Ok I understand your explanations about ABS parts and your "garbage chamber". Maybe I'll try to print ABS parts with my Prusa for the second TAZ .

I could be interested in your work on the plate. I wouldn't like to abuse of your time and fear a bit about a drop in shipping as you'll have to send it to France. Possibly for one plate ? Would you have some estimate about shipping ?
Here is the original design of the mount plate with holes for bearing hloders and Y axis belt piece (and four point attach system ) : [devel.lulzbot.com] .

I would opt for 400 W. Original TAZ is designed with 300W power supply (and without garbage chamber) and it seems to work globaly despite some slight issues. If Yvan wants more, no problem.

And no problem Yvan, 12"x12" will be fine .

If there could be other interested people that would be cool .

@Parabolic

Yvan is right, we completely took over your thread Sorry about that. If you want I can get you a silicone rubber heater that is 13"x10" but I really don't know where you will find a PCB heater that size.

@Yvan

I checked out the design and it looks like it has some serious potential I can't really tell from the render but is the y-axis motor inside the chamber? It looks to me like the only motor that needs to be inside the chamber is the extruder motor, which will probably get really hot seeing as it will be directly above the heat bed You may want to consider a fan with ducting to pull cold air from outside the chamber to cool the stepper. I have fans on all my steppers inside the garbage chamber at 40C and they are still pretty hot (though there has not been a noticeable decrease in performance). As for the enclosure, you could easily get away with acrylic windows rather than using polycarbonate. Since the fame is made of MDF, the windows are not structural components so the minor warping that acrylic will experience at those temps will not distort the frame. In this case, the extra cost of polycarbonate would not be worth it in my opinion.

So is anyone else interested in ordering a custom silicone rubber heat bed? (It doesn't have to be 12"x12"). Ordering 3 for Couby and 1 for Yvan is doable but it would be better if more people were interested

Eric

@Couby

It looks like 400W would be sufficient. I suppose I overestimated quite a bit

Shipping three 12"x12" heaters plus two laser cut MDF sheets (for 1 bed mounting set up) to France would be about $120.

I checked the Lulzbot drawing and I could definitely draw up a mounting system that incorporates the existing bearing/y belt mounting holes. It might take some time though... Also, I realized that I cannot fit the dimensions for the MDF plates on the stock that I have so I will have to buy slightly larger sheets of MDF for this so I will have to charge you 70 dollars for the 2 mounting plates for 1 bed mounting set up Sorry about that.

Let me know what you think.

Eric

RP Iron Man Wrote:
-------------------------------------------------------
> @Parabolic
>
> Yvan is right, we completely took over your thread
> Sorry about that. If you want I can get you a
> silicone rubber heater that is 13"x10" but I
> really don't know where you will find a PCB heater
> that size.
>
> @Yvan
>
> I checked out the design and it looks like it has
> some serious potential I can't really tell from
> the render but is the y-axis motor inside the
> chamber? It looks to me like the only motor that
> needs to be inside the chamber is the extruder
> motor, which will probably get really hot seeing
> as it will be directly above the heat bed You
> may want to consider a fan with ducting to pull
> cold air from outside the chamber to cool the
> stepper. I have fans on all my steppers inside the
> garbage chamber at 40C and they are still pretty
> hot (though there has not been a noticeable
> decrease in performance). As for the enclosure,
> you could easily get away with acrylic windows
> rather than using polycarbonate. Since the fame is
> made of MDF, the windows are not structural
> components so the minor warping that acrylic will
> experience at those temps will not distort the
> frame. In this case, the extra cost of
> polycarbonate would not be worth it in my opinion.
>
>
> So is anyone else interested in ordering a custom
> silicone rubber heat bed? (It doesn't have to be
> 12"x12"). Ordering 3 for Couby and 1 for Yvan is
> doable but it would be better if more people were
> interested
>
> Eric


I'd be up for ordering at least one or two of these as well.

Damn, didn't think that would be such price.

What would be the shipping approximately just for the three heaters ?
Sorry I have to consider this shipping aspect .


RP Iron Man Wrote:
-------------------------------------------------------
> @Couby
>
> It looks like 400W would be sufficient. I suppose
> I overestimated quite a bit
>
> Shipping three 12"x12" heaters plus two laser cut
> MDF sheets (for 1 bed mounting set up) to France
> would be about $120.
>
> I checked the Lulzbot drawing and I could
> definitely draw up a mounting system that
> incorporates the existing bearing/y belt mounting
> holes. It might take some time though... Also, I
> realized that I cannot fit the dimensions for the
> MDF plates on the stock that I have so I will have
> to buy slightly larger sheets of MDF for this so I
> will have to charge you 70 dollars for the 2
> mounting plates for 1 bed mounting set up Sorry
> about that.
>
> Let me know what you think.
>
> Eric