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Complete heated bed kit for Ultimaker

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Posted · Complete heated bed kit for Ultimaker

That sounds like a slack joint...

I actually had one myself with my SIlicone heater (won't buy one of these anymore...)

How are the wires connected to your heated bed? Maybe you can see if the cables aren't properly soldered, or maybe there's a connector which may be broken.

If you have a Multimeter or Oscilloscope, you should check the cables.

About controlling the heated bed by adjusting voltage instead of PWM:

The "best" thing to do would be to use an adjustable current source (not voltage, but current!).

But as a matter of fact, PWM is both waaaaay simpler and even more energy efficient (when done properly, meaning when you're using a good, fast switching MosFET with low On-Resistance).

If Bang-Bang mode is not good enough for you (my Bang-Bang heatbed actually regulates without moving a single °C...), then you could set-up the PID regulator. When properly done, this should get you stable regulation in the +-0.1 °C range.

 

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Posted · Complete heated bed kit for Ultimaker

Hi Jason.

As Martin says I see you have both your kits in stock, the original Heated bed and the glass upgrade but there is no premium package (combining them) available. Do you plan to offer them as a single item anymore or do I have to order both separately?

 

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Posted · Complete heated bed kit for Ultimaker

@michel - I think something is loose - keep poking around to figure out where the bad connection is but if it only happens when you poke the thermister then it must be very close or on the thermister.

 

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Posted · Complete heated bed kit for Ultimaker

BANG BANG versus PWM

For heated beds - because they take so long to heat up - and unless they are very much overpowered, I think bang bang is good enough for something like 1 degree C accuracy - especially at the very high temperatures near the limit of what the bed can do e.g. over 90C.

If you can heat the bed from 20C to 70C in 4 seconds then obviously you need a PWM controller as you will be getting massive overshoot if you don't. But if it takes a few minutes to get up to temperature then "bang bang" mode should be fine. It's all about how much it over shoots when you shut if off.

My bed has zero overshoot - well - less than 1C so bang bang is fine. Similarly if the bed is off and cooling and the thermostat turns the bed heater back on but it overshoots in the downward direction (goes down >4C even though heater is on) then you also would want PWM. But I doubt that you will see this with Jason's kit.

 

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Posted · Complete heated bed kit for Ultimaker

BANG BANG versus PWM

For heated beds - because they take so long to heat up - and unless they are very much overpowered, I think bang bang is good enough for something like 1 degree C accuracy - especially at the very high temperatures near the limit of what the bed can do e.g. over 90C.

If you can heat the bed from 20C to 70C in 4 seconds then obviously you need a PWM controller as you will be getting massive overshoot if you don't. But if it takes a few minutes to get up to temperature then "bang bang" mode should be fine. It's all about how much it over shoots when you shut if off.

My bed has zero overshoot - well - less than 1C so bang bang is fine. Similarly if the bed is off and cooling and the thermostat turns the bed heater back on but it overshoots in the downward direction (goes down >4C even though heater is on) then you also would want PWM. But I doubt that you will see this with Jason's kit.

 

Thank you for your explanation.

Can it this be you have mistaken PWM for PID? I think PWM and Bang Bang is the same?

Greetings

 

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Posted · Complete heated bed kit for Ultimaker

For PWM you switch on and off x times per second (40 or 100 times). A simple relay can not switch that fast. So in PWM you regulate the duty cycle. And in bang bang you turn on until the temperature is reached, and when it gets too cold you switch on again. This typically takes x amount of seconds.

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Posted · Complete heated bed kit for Ultimaker

PID is implemented by varying the pulse width time (PWM). So PID and PWM are related. Bangbang is a slow on and off cycle and is determined by the temperature falling below the desired temp by a certain amount causing the relay to switch on until it is above the set point by a certain amount. That on and off might take several seconds. PWM switches on and off many times a second trying to supply just enough power so that the temperature is kept very close to the desired temp.

 

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Posted · Complete heated bed kit for Ultimaker

Has anyone had any issues with borosilicate glass breaking or failing? I just installed Jason's heated bed hit (works great by the way) but orded some glass from somewhere else (

Has anyone had something like this happen? Do I need to put anything on top of the glass before I print (like PVA or a glue stick?) or should I be able to print directly on the glass?

Thanks in advance for any suggestions. I guess I should order some glass from Jason this time...

-Daniel

 

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Posted · Complete heated bed kit for Ultimaker

@ gr5, really good post (reading it once more made me again aware of many things). thanks!

I have just installed the Jason HK HBK and I need to say it all went very smooth from order to installation. I went for the full thing. So the HBK itself, the borosilicate glass add-on and even the power supply. This should be a short summary of my findings and some kind of installation blog light.

This is already the 3rd iteration of the kit and you feel that right away when it arrives. The 3mm aluminum plate feels solid and the pre soldered connector seems strong. The relay module is very nicely put together and soldered also. The pre-assembled cable (power and heat sensor, thermistor) with female connectors fit perfectly and the length is just right. The wires are of good quality as far as I can tell (ratings are on the wire, but can’t recall). There is also a 4.7k ohm resistor included in the package to be soldered onto your UMs board (R4). The kit even comes with additional / extra cable to connect VCC / Control UM's board to the control relay!

I have always wanted to keep my UM1’s heated bed completely separate so I went for the 2nd Power Supply which was supposed to be switch on / off independently from the main power. I still want to print cold / blue tape with alcohol so I thought it would make sense not to combine everything together.

On to installing it, first, removed my “old” acrylic bed, removed all screws and just replaced the springs with the ones supplied with the delivery. The springs are wider, longer and stronger. This meant that after installing the Alu plate and the glass, I only had to adjust the Z-Stop slightly. And no, I did not convert it to 3 point leveling; I am still ok with 4 points (I know, I should do it anyway).

Afterwards it was time to connect the cables, solder the resistor onto the UM Board and connect everything according to the plan on ebay. Worked great, no issues there. Afterwards, connect all the power and ON. No shorts at least, so chance that hardware were installed correctly.

To Marlin: I thought to be smart and installed the standard “heated bead firmaware” that is issued with Cura 14.06. Ups. After initially showing the bed etc. it only shows a strange error message on the UltiController and hangs! No more connection anymore via computer / usb. Panic (a bit)! So, load the standard firmware in Cura, power off UM, remove USB. In Cura press load firmware and only then connect the usb cable to the Arduino. WORKS, it starts the firmware update before initializing! Great. So I guess not my thermistor in the Standard Cura firmware. I compiled my own Marlin with the correct settings, loaded it and all just works!

First, with all temporarily installed I print a case for the power switch also one for the relay board. It prints very nicely on the heated bed. After the prints, cut out the piece for the power switch (including fuse and on off switch with LED) and drilling the holes for power supply, relay and power switch. Connect everything together, screw the stuff to the UM, add some nice cable management and here we go. Fin.

I hope that helps the guys that are still to install one. Also find some pictures attached:

hbk1hbk2hbk3hbk5hbk4HBK Jason HK Schematics

 

Edit: Still need to do add a nice cable management solution from the bed downwards... if you have any ideas, appreciate it.

 

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Posted · Complete heated bed kit for Ultimaker

Can the bed also be mounted with the connector on the left? If yes, then Robert's cable chain, modified by drayson for the UM1, is a quite nice solution.

I'm not sure if there is enough space on the right but maybe it can even be mounted there (the bed end piece would have to be mirrored).

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Posted · Complete heated bed kit for Ultimaker

indeed, it can just be turned around to have the connector on the left side... I did this and are planning on the modified cable chain

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Posted · Complete heated bed kit for Ultimaker

Thanks guys. Tommyph1208, can you add a picture of yours?

 

Will do when I get home.. I haven't made the cable chain yet though... Just modified the bed a bit for 3 point leveling and stuck it in there...

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Posted · Complete heated bed kit for Ultimaker

Here are a few images of my Z-stage with Jasons kit incl. the borosilicate glass...

Z stage with Jasons Aluminium Heated bed kit, incl. borosilicate glass

Z stage 3-point leveling

As I mentioned, I modified it for 3 point leveling.

I drillied a new hole in the front center of the z-stage bottom plate and moved one of the little black plastic fittings in there. I also needed to drill out the hole in the aluminium plate a bit, and make the "keyhole" shape to accomodate the snap on system.

The Borosilicate glass kit came with 4 thumb-screw like nuts, so I chose longer bolts to hold the bed and screwed them all the way through the fitting and out on the bottom side of the bed. I then put the thumb-screw nuts on there with some superglue in the threads... (remember the springs and spacers before glueing the nut on, as the bolt won´t come off again).

Thats basically it, I think the end result is quite nice, and will be even nicer with the cable chain...

 

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Posted · Complete heated bed kit for Ultimaker

Thats basically it, I think the end result is quite nice, and will be even nicer with the cable chain...

 

I have just installed my Jason HK heated bed.

I have printed the cable chain from https://www.youmagine.com/designs/heat-bed-wire-clip-for-um-original-remix to accommodate with the 4 cables coming with the kit. I am quite happy with the result:

 

20140630 222125

 

I use a common 24V 15A power supply both for the heated bed and the original electronics. Everything went smooth except some random clicks of the knob when the heated bed is switched on. I suspect some EMI coming from the high current and disturbing the gray ribbon cable of the Ulticontroller. I have solved the issue with some filtering in Marlin firmware.

 

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Posted · Complete heated bed kit for Ultimaker

... just a quick update on my Jason_HK HBK installation. The Relais is dead (the one on the board supplied with the kit), probably burnt it's contacts together (how do you say that in proper english?). I do not want to cause any panic but that drove my HB to over 110°. Luckily I constantly monitored the print and was able to pull the plug. I also use the PSU that came with the kit and regulated it as far down as I could (20V, that's probably still 10 AMPs).

Will now replace the relais with either a solid state, stronger car relais or a MosFET.... :-| probalby MosFET. JonnyBischof has a nice diagram in one of his posts so I will try to modify the existing board to fit a MosFET.

@JonnyBischof, would you be so kind to suggest a MosFET (Switzerland)... I think the one in your schematics is obsolete?

 

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Posted · Complete heated bed kit for Ultimaker

... just a quick update on my Jason_HK HBK installation. The Relais is dead (the one on the board supplied with the kit), probably burnt it's contacts together (how do you say that in proper english?). I do not want to cause any panic but that drove my HB to over 110°. Luckily I constantly monitored the print and was able to pull the plug. I also use the PSU that came with the kit and regulated it as far down as I could (20V, that's probably still 10 AMPs).

...

 

That's why it's best not to overpower the heated beds ;)

My bed would probably never go past 120°C even when fully powered for hours. But I may be wrong, I never actually tested it... I'm using a 24V, 100W MK3 Aluminum PCB heater.

 

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Posted · Complete heated bed kit for Ultimaker

...

Will now replace the relais with either a solid state, stronger car relais or a MosFET.... :-| probalby MosFET. JonnyBischof has a nice diagram in one of his posts so I will try to modify the existing board to fit a MosFET.

@JonnyBischof, would you be so kind to suggest a MosFET (Switzerland)... I think the one in your schematics is obsolete?

 

UM heatbed mosfet wiring

It isn't obsolete, but I misspelled the model type:

http://ch.mouser.com/ProductDetail/International-Rectifier/IRFB3004PBF/?qs=sGAEpiMZZMshyDBzk1%2fWi5%252bqVgN3%252bWS8WtSECkw%252bUZk%3d

The correct model type is "IRFB3004PbF"

However, there are dozens of other candidates.

What you need to look for:

1. package that you can work with. TO-220 (and similar subtypes) is usually ideal. D2Pak is much more difficult to solder by hand, because they miss one tab (SMD only)

2. VDS (Drain Source voltage) maximum must be higher than your heated bed voltage.

3. VGS (Gate Source voltage) max should be higher than 12V (OR you can modify my circuit, see below).

4. Smallest RDSon you can find (1.5 mOhm is perfect, but actually, much more is tolerable. I would take something that has less than 20 mOhms though).

If you're looking for new parts, I usually prefer International Rectifier's "Strong IRFet" line. These are among the most expensive parts in their spec range, though...

----------

About VGS:

The Gate-Source voltage is what you use for switching the MosFET. You have to be careful to supply an appropriate voltage, or the MosFET will not switch as intended.

If VGS is too low, then the MosFET will not open, or not fully open. If it's too high, the MosFET will be damaged.

VGS max is always indicated in the datasheet under "absolute maximum ratings". You should select a voltage at least 20% lower than VGS max.

Then, there's another indicator: VGS th (VGS threshold voltage) which indicates the minimum voltage required to switch the MosFET. Note that VGS th is what it takes to open the FET "minimally", and you should always select a higher voltage than VGSth.

Example with IRFB3004:

VGS max: 20V (so NO 24V direct!). You could supply the 19.5V from the UM original PSU, but that's very close to the "absolute max rating". Not very elegant, and prone to failing sooner or later. (Or it could work for 20 years, you can never tell for sure with electronics)

VGSth: 4V. So you couldn't switch this MosFET reliably from an Arduino's 3.3V output.

I went with VGS = ~ 10V because that was easy to achieve, I just divided the voltage (19V from the UM original PSU) in half with the voltage divider you see in the picture above.

Note that this solution is far from professional. But it works, as long as you take ESD safety precautions.

 

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Posted · Complete heated bed kit for Ultimaker

Thanks. I will order one. Then I will need to see how I can modify the board to get it going. It looks pretty similar to your setup but I will need to verify that. Also I will need to switch to GND switching vs. V+.

HBK Jason HK Schematics

Would you say that 200W are overpowered for the solution? Should I replace the PSU with a 120W or similar? Will the MosFET be (to) hot at 200W (event it has a very low resistance)? Sorry... long time no electronics (analog at least)....

 

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Posted · Complete heated bed kit for Ultimaker

The power is defined by your heater. If your heater "needs" 200W (meaning, if it is a 200W heater), then you have to supply 200W, or your PSU will be overpowered and fail (industrial PSUs just deactivate their output due to the "overcurrent protection"). *

It's difficult to say what amount of power is ideal. On one side, a 200W heater will heat up considerably faster than a 100W one (especially past 70°C where my heater takes AGES). On the other hand, the UM original construction is somewhat fragile (electronics wise). It takes a lot until something starts to actually burn - it would probably never happen even with a 300W heater. But I'm not an expert at burning stuff, so I'm usually cautious.

The MosFET will not have a problem at all. You can put about 100A through it (2.4 kW at 24V), and probably up to 50A without cooling. Theoretical limit of the IRFB3004 is 195A, but that's really just theoretical...

Your wires, solder joints, and (worst of all) PCB strips will fail a lot earlier than the MosFET.

*: I've explained this in detail here

 

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Posted · Complete heated bed kit for Ultimaker

I have Jason's V2 heated bed and I am driving it with a 280 watt power supply. As Jonny mentioned, the bed is what defines the power requirement. Jason recommends a 24V 10 amp supply which is 240 watts so it's safe to assume the bed draws less than 240 watts.

Jonny's circuit is good. However, if you want an "off-the-shelf" solution, I'm using a somewhat expense (30USD) SSR from phidgets.

See this thread for details on how I hooked it up -

http://umforum.ultimaker.com/index.php?/topic/6014-heated-bed-build-and-a-question-about-the-z-stage/?p=55276

 

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Posted · Complete heated bed kit for Ultimaker

thanks anon 4321, I will go with Jonny's solution for now, as I think I can modify the existing board without to much pain and without much cost. SSR only if everything else fails...

 

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Posted · Complete heated bed kit for Ultimaker

I did install / modify the existing board. Added the voltage divider and the mosfet, switched to ground switching, tested, works. Back to printing warm. I still wonder a bit why I did not install the MosFET from the begining.

Thank you everybody for your help.

 

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