Just wanted to say Hi.

Hi Guys and Girls,

I'm new to the building of 3D Printers but have watched them grow and have been amazed by what they can do.

I studied Games Design in Uni and did quite a bit of 3D modelling then but since haven't really touched any 3D modelling.

Life getting in the way and my main PC going bang and not having the funds to fix it.

I haven't started my build as of yet but I have the ordered the aluminium extrusions/motors/power supply and I will buy the rest when I have the money.

I'm going to be building mine on a CNC based design with a fixed build platform and a moving Gantry that carries the extruder.

It will hopefully have a build platform of around 400 x 400 x 500 with a dual extruder.

I'm having issues working out how to heat a bed of that size on the cheap and considering building a heated chamber to help it along.

I hope to learn loads from here.

Cheers Ryan.

Edited 1 time(s). Last edit at 10/15/2016 06:56AM by Rlewisrlou666.

Welcome to the forum.

Large (flat) heated beds of that size are indeed difficult to do on the cheap. The standard answer is aluminium tooling plate with a mains powered silicon heater. One way to get started is to postpone the heating until later and use a piece of sacrificial foam to print on. Because the nozzle will be set to penetrate into the foam a small amount, flatness becomes less critical too. You could probably build the bed carrier from mdf or plexi in this case.

Edited 1 time(s). Last edit at 10/15/2016 10:22AM by JamesK.

Thanks for the reply JamesK

I have a sheet of 1.5mm Aluminium that I've been saving for a project. I'm was thinking of using that as a bed with a coating on it.

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Rlewisrlou666
Thanks for the reply JamesK

I have a sheet of 1.5mm Aluminium that I've been saving for a project. I'm was thinking of using that as a bed with a coating on it.

1.5 mm thick will not be enough it will warp under heat like a good un? Would recomend you look at some 5mm or even thicker cast Tool plate for your bed and takeing your size would defo go for 6 or thicker but 6 should be enough at 400 sq

At that size you will also need something like a 800 watt heater (Unless you want to wait ages for the bed to get to temp) this is based on the recomended 0.5 watt per sq cM rule.

Doug

Agreed, I expect 1.5mm would be too thin. You'd need to look at making a composite out of it to have any hope of keeping it flat, and every time I suggest that, the more experienced members laugh at me 1/4" tooling plate looks very good for the standard 200mm² bed, and I think it would probably be ok at 400mm, but it's possible you might need to go to 3/8". It gets very expensive unless you have a local metal supplier that you can pick up from (or if you are in the USA where shipping prices are often much more reasonable than most of the rest of the world). I'm trying to convince myself to pay up for tooling plate for my next printer, but I want to see the rest of it working first.

Thank you for the advice guys I'll ask my Brother In Law what sheet metals they do at his place.

@dougal1957 - Would I be able to run a heater of that wattage through an SSR to make it more usable without the need for a 1000w Power Supply?

@JamesK - I was thinking of making a composite of FibreGlass and Aluminium.

1.5mm Aluminium
400 x 400 silicone heater
2mm fibreglass
1.5mm Aluminium

The bed is going to be Static and I'm thinking of mounting it in the corners and centres of each side on springs.

I've got a proximity sensor so i'm not to worried about levelling the heat bed manually every time.

I didn't fancy twiddling 8 screws and sliding paper around the bed.

Hey Ryan, so that's very much the sort of bed construction that gets me laughed at Personally I'd like to see it done, because I'm pretty sure it's possible, but you should be aware that it's definitely a case of doing it the hard way, and might turn out to be impractical. So what sort of issues might you run into? If the heater is on the bottom of the composite the bottom layer of aluminum will get hotter before the top pieces, especially with fibreglass (an insulator) in between them. The differential expansion will try and force the composite into a sphere unless you allow for the layers to move independently. Similarly, the coefficient of expansion of the aluminum and fibreglass layers is likely to be different, so even at a constant temperature those will try and warp unless they can move separately. Level is not the same as flat, and the requirement for flatness is quite severe if you want to use a small first layer. My current print surface is very non-flat, so I compromise with a thick first layer which is severely squished over parts of the build. Even so I struggle with full plate parts - first layer adhesion is critically dependent on the Z=0 height from the bed. That said, some firmwares have started to incorporate bed mapping and compensation for non-flatness, but I don't know how well it works. In general, a lot of people have problems getting even basic leveling correction working reliably, and even if it works it means that the Z axis has to continually operate in non-full step increments - that's not a recipe for accurate layer extrusion. This is one of those cases where doing it right is definitely doing it better. (But, I also want to try auto bed leveling one day to see just how well it works for myself. What can I say, I suffer from excessive curiosity.)

I think, if you want to try and fabricate a bed from a thin plate, the way to go is probably to stick to a single material by using aluminum angle to stiffen the surface. I believe that the Lotus Elise had an aluminum chassis that was largely glued together. I'd love to know if that's a practical way to fab a base plate, given the temperatures it's subjected to. You'd need a fair bit of insulation under the bed to stop the Al angle acting like a heat sink and cooling the bed, but that's doable.

edit: the other issue that will get called out is the mounting screws. It's obviously possible to have many mounting screws on a sufficiently rigid bed, but you do have to make sure that any tendency to bend the bed is either insignificant compared to the bed rigidity, or you have a way of tuning it out by accurate measurement and find adjustment of each screw. Three point mounts are the frequently championed alternative because of the simplicity of adjustment, but also require a very stiff bed because large areas are completely unsupported.

Edited 1 time(s). Last edit at 10/15/2016 08:01PM by JamesK.

You need to read up on our "Digital Dentist's" topic on his latest large heatbed project. I'm sure he'll list it when he reads this post.

@JamesK - You won't ever get laughed at by me by asking questions that sometimes need to be asked. I suffer with excessive curiosity too.
Most beds I've seen even on pro models are composite in some form. Frame/PCB-Silicone Heater/Build Plate/Glass all held together with bulldog clips so it's not a crazy idea it just takes the right materials.
Auto Levelling is cheap to implement you only need a proximity sensor I bought mine for £4 from Amazon I was thinking about buying some more and replacing the endstop switches with them as I will have an all Aluminium Frame.
I'm thinking of this as a CNC that adds material instead of taking it away.
If the machine and bed are level and as flat as can be then the X and Y Axis can be trued up to that as much as possible not much can/should go wrong.
If I have to build a thicker more solid Build Platform then so be it but it doesn't mean I can't have a bit of fun playing around before I get to that point.

@elswood127 - I'll have to see if I can find it thanks for the heads up.
I started reading the Digital Dentists Instructable on Son of MegaMax when the kids are back in School I'll have a good read without being disturbed.
I noticed there was a lot of talk about precision/rigidity and thats what I'll be going for.
His build looks like an awesome Machine but to build something like that is way out of my price range I'd have to sell one of my kids.
I really do like it and it is similar to what I had in mind for my build from a construction stand point anyway.
Mine will have a fixed build plate and the X and Z will be supported on a gantry that rides on the outside of base frame in the Y.

Thanks again guys.

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If I have to build a thicker more solid Build Platform then so be it but it doesn't mean I can't have a bit of fun playing around before I get to that point.

With you all the way on that one Ryan. Hobbies are supposed to be fun, right? I have some wild ideas I'm playing with at the moment for a peltier based heat bed so that at the end of the print I can reverse the current and cool the print surface I did briefly think about making a sandwich with the peltiers in between two layers of Al, but that's asking for the heat bed to banana as one side heats and the other cools. Plus, I suspect that uneven heating of the surface is likely to be an issue, so having all the aluminum on the top side seems like the right approach. I've made a quick test rig with four peltiers on a 200mm² plate and it heats up ok. Haven't checked the cooling aspect yet, but since that's less critical than heating I don't expect any problems. Heatsinks and fans on the underside of the peltiers will disperse the heat.

That would be pretty wild.
Not sure how the electrical contacts would handle rapid heat and cooling cycles you would have to test it before hooking up to your printbed.
Heat to 100C leave for 5 mins cool to Ambient Temp Cycle increasing the max temp time each time till something fails. You don't want to fry anything Major. I like your style of thinking though.

Printing onto a Cooled bed would be really good for things like Chocolate or Sugar too as they need to cool quickly.

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Rlewisrlou666
Thank you for the advice guys I'll ask my Brother In Law what sheet metals they do at his place.

@dougal1957 - Would I be able to run a heater of that wattage through an SSR to make it more usable without the need for a 1000w Power Supply?

If it were me (Especially as you say your bed will be static) then go for an AC Heater driven with an SSR (Get a good one rather than a clone tho) my current build has a 300mm diam 350W heater with no probs at all driven with an SSR the build I am on with I am about to order a silicon heater for it that will be 1.5Kw run from a SSR and 240Volts AC (This is on a large delta with 650mm Diameter bed).

Doug

p.s. Do not try to go with a low voltage one driven from the control board it will not cope with the current requirement and dc SSR's unless you spend the money on them just drop to many Volts and generate a lot of heat!!

Thanks again Doug,
I watched Toms Hardware video on SSR's as he just upgraded the heater to a Silicone for his Delta, looks like I'm shopping for a large wattage heater.

Check this site. You may be surprised how cheap it would be to go extruded frame.

[www.adafruit.com]

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elwood127
Check this site. You may be surprised how cheap it would be to go extruded frame.

[www.adafruit.com]

I build my printers out of aluminium square tube, you can get 1" square for $23 CAD in 8 feet lengths at home depot. You have to work a little harder to join it together than with extrusion, but it's easy to drill and tap. Pieces of right angle extrusion can hold the corners in alignment and steel plates with #10 screws passing right through the tube will hold everything planar and very rigid.

Thanks for the link elwood127 I'm in the UK though.
I'm building with Extruded Aluminium I've ordered some 2020 and some 3030.

I watched a tonne of CNC builds that are made from Extruded Frame and they are massive machines I think the one build had something like 10x5ft build platform with 4ft of that dropping to the floor to handle taller pieces.
I was really impressed with how strong it was, I think I made my mind up then.

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Rlewisrlou666
Thanks for the link elwood127 I'm in the UK though.

Where in the UK

I you want good Aluminium Toolpalt look at [www.aluminiumwarehouse.co.uk] look at ecocast in the Plate section 6mm thick is a good solution
When it comes to mounting it use just 3 screws 2 corner and centre of the opposite side any more than this and you may find it extremely difficult to level without introducing a twist in the plate.

Good place for extrusion is www.motedis.co.uk (There actually in Germany) they do a good range and will cut to size FOC and very competitive pricing. If you want proper V-Slot then look at www.ooznest.co.uk.

HTH

Doug

@Doug - I'm in Chepstow,

I found Aluminium Warehouse reading another post earlier I'm going to be ordering my plate from them as I thought the prices were awesome. That's if my brother in Law can't get me some from his works.

I found a PCB supplier that will sell me some copper clad in the size I need I just have to design something to etch onto it or find someone who knows how to work eagle that can help me design a Gerber file to send to them for a price on making the heater for me.

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Rlewisrlou666
@Doug - I'm in Chepstow,

I found a PCB supplier that will sell me some copper clad in the size I need I just have to design something to etch onto it or find someone who knows how to work eagle that can help me design a Gerber file to send to them for a price on making the heater for me.

I would forget the PCB idea if I were you and look towards a silicon one see 400x400 silicon heater this is just an example but if you contact them they will make you one to your requirements they have just quoted me $77 US for a 630mm diameter 1500W one with a small hole in the centre so I can mount my own Thermistor where I want it to be.

I am near Chesterfield by the way if ever you need any help?

Doug

p.s. have you decided what electronics you will be using?

They just quoted me £77 just for the copper clad board on it's own so I think I will be leaving that idea for now.

Having a Thermistor in the centre sounds like a great idea depending on the thickness you could also install an LED not sure how practical it would be printing in black or anything like that but would look great printing white.

I was thinking Ramps but then the more I looked I started noticing that the newer boards are 32bit and don't know if I should spend a bit extra and go for one of those now rather than upgrading at a later stage. Only problem with them is the price on some is too high for me.

Any suggestions or advice would be greatly appreciated.

I just ordered another RAMPS based electronics package. You can't beat the value at around 30 USD including the graphical LCD (so thats mega2560, ramps, 5xdrv8825 and the LCD). Duet wifi looks like the outright best designed controller card to me, but I find the price intimidating in the short term. There's no doubt that 32bit is the way to go in terms of ease of use and increased ceiling for high step rates. I have been wondering about getting one of ST's 32 bit evaluation boards which are very reasonably priced and adding my own interfaces to stepper drivers and mosfets. But realistically it would be a lot of work to get up and running and I have too many pipe-dreams already in the queue. This weekend I modified a spare RAMPS to remove D1 (that sends the 12V input to the mega2560 Vin) and set it up with a new PSU running at 13V with a boost converter to produce 7.5V from the 3.3V stand-by for the mega. Works a treat. With this setup I may opt for a 25V supply in the next build.

Edited 1 time(s). Last edit at 10/17/2016 01:20PM by JamesK.

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JamesK
I just ordered another RAMPS based electronics package. You can't beat the value at around 30 USD including the graphical LCD (so thats mega2560, ramps, 5xdrv8825 and the LCD). Duet wifi looks like the outright best designed controller card to me, but I find the price intimidating in the short term. There's no doubt that 32bit is the way to go in terms of ease of use and increased ceiling for high step rates. I have been wondering about getting one of ST's 32 bit evaluation boards which are very reasonably priced and adding my own interfaces to stepper drivers and mosfets. But realistically it would be a lot of work to get up and running and I have too many pipe-dreams already in the queue. This weekend I modified a spare RAMPS to remove D1 (that sends the 12V input to the mega2560 Vin) and set it up with a new PSU running at 13V with a boost converter to produce 7.5V from the 3.3V stand-by for the mega. Works a treat. With this setup I may opt for a 25V supply in the next build.

IMHO the only controller out there at the Moment is the DUET Series followed closely by the Smoothie.

If you are running a Delta style machine then the 32 bit definately pays off I have 2 Duet WiFi's here (One is one of the Beta test boards and the other is an early adopter one but have also had 4 Duet 0.6 boards and they all perform well.

(you can get the 0.6 from reprap for about £60 which IMHO is a bargain but there won't be many left now.)

they all have the excellent web interface. the WiFi however has superb Stepper drivers on it they are just so quiet.

I Still have a spare 0.6 which may well get re-purposed for my CNC Machine?

Doug

I couldn't find any Duets for that cheap.

I was looking at the RADDS but they need an Arduino Due so £40 for the RADDS + £25 for the Due and you are looking at £65 plus the extras on top of that drivers and everything else.

I get this when looking for the Reprap shop.

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Rlewisrlou666
I couldn't find any Duets for that cheap.

I was looking at the RADDS but they need an Arduino Due so £40 for the RADDS + £25 for the Due and you are looking at £65 plus the extras on top of that drivers and everything else.

looks like the cost has risen to £74 but see Duet 0.6

I can vouch foir the supplier tho never actually used him he is one of the original Director's/designers @ reprappro

Doug

T3P3 still sells Duet 0.6 boards as well as the 0.8.5 and WiFi. See [www.think3dprint3d.com].

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42
T3P3 still sells Duet 0.6 boards as well as the 0.8.5 and WiFi. See [www.think3dprint3d.com].

Didn't re-alise that Tony still did the 0.6 boards so I stand corrected

Doug

It seems that the Duet is out of stock from that link.
I'm sure one will come up at the right price.
Thanks for the help Guys.

the Link I gave to Emaker.io is still showing as in stock?

Doug

Thanks Doug I just hope they are still in stock when I have the money to buy one.