1 Topic by slimstar2

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Topic: Dual bed heaters ???? Any thoughts?

http://soliforum.com/i/?IxTkpqO.jpgThis is an open question asking for opinions  from all the gurus here who have helped me so many times in the past.

(WardJr, Pirvan, Azerate, Tin Falcon and all others with comments )

A little background;      After having sticking problems on larger prints I took some ones advice and replaced the original SD 3 bed heater with a bigger, more powerful one I got on Ebay ( $24  holes were slightly off ) bigger power supply SSR and PID tuning on the bed heater. Original SD 3 heater pulled 8 amps @ 15 volts . New heater pulled 25 amps @15 volts, 5 minute heat up time, for about 5 months then suddenly dropped to 8 amps . Oh well , I bought another, same amp draw etc, three months later  same thing amp draw dropped 8 amps heat times tripled. Emailed the seller he graciously sent me a replacement for just $4 shipping . That one lasted 2 months . When I tried to buy another the listing was gone from Ebay. Emailing the seller I was told he didn't have anymore . Oh well, time for plan "B"  .

Plan "B" is an experiment , I bought a Prusa PCB type , drilled a tiny hole in the SD 3 aluminum plate and mounted the Prusa on top with a tiny single screw , leaving the silicon heater and the insulation on the bottom of the aluminum bed . I powered up the Prusa and it drew 8 amps and took 15 minutes to heat to 95 C . Virtually the same as replacement pads when they went bad . I reran the PID tuning 3 times, very consistent , but to slow. Time for plan  "C".

Plan "C" is is to combine BOTH heaters !! I have hooked them up to the SSR (100 amp rated) in parallel , combined they draw 28 amps at start up and drops to 25 amps after about 1 minute . Heat up time is back to 5 minutes after rerunning PID tuning 3 more times, very consistent. Although it does overrun set temp initially by about 8 degrees C it settles back to set point in about 1 minute and remains rock steady after that. The power consumption graph shows that it is not working very hard to maintain set temp ( approximately 10 %). I am trying my 1 st large print right now, it is a slightly modified version of the camera tower for the Atlas 3 D scanner .I have tried this print 3 other times and have had minor lifting problems. So I am trying it again with this set up , I will post results when it is  done . I am keeping fingers crossed.

I tried to use screen shot of temp graphs  in Repitier but it doesn't seem to work .

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SD3, RAMPS 1.4, Lawsy's carriages modified by me, 2 SSRs, E3D V6, 2 Power supplies, Independent monitoring of both power supplies (amps and volts) also extruder and bed temps, Blue Tooth connectivity, bearings in all axis & rotational points, Y axis direct drive.  Remotely controlled power box on / off . Gecko Tec build plate . Renamed FrankenDoodle

2 Reply by wardjr

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Re: Dual bed heaters ???? Any thoughts?

At least you'll have some redundancy built into the system wink
I can tell you that over run of initial heat up can be very difficult to avoid with larger heaters.

Printit Industries Model 8.10 fully enclosed CoreXY, Chamber heat
3-SD3's & a Workbench all fully enclosed, RH-Slic3r Win7pro, E3D V6, Volcano & Cyclops Hot End
SSR/500W AC Heated Glass Bed, Linear bearings on SS rods. Direct Drive Y-axis, BulldogXL
Thanks to all for your contributions

wardjr's Website

3 Reply by AZERATE

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Re: Dual bed heaters ???? Any thoughts?

I can't chime in on the upgraded bed heater side of things since I haven't done it personally.
But I recently got my #1 printer back up. Both printers are SD2s with the same Supernight PSU, Sang boards, and stock bed heaters. While dismantling #1 for Rumba and Bulldog upgrades, I kicked the output voltage up a hair. My bed now heats up in the 5-8 minute range whereas before it was close to 45min.
#2 is at the 45min mark since I matched the voltage of #1's before upgrading the latter.
So basically what I'm saying is; if you have upgraded you PSU and can adjust the output, try that. Just be sure you don't Over power yours board.

Printit Mason and Printit Horizon printers
Multiple SD2s- Bulldog XL, E3D v5/v6/Lite6, Volcano, Hobb Goblin, Titan, .9 motor, Lawsy carriages, direct Y drive, fishing line...the list goes on
Filawinder and Filastruder #1870.....worth every penny!

4 Reply by slimstar2

  • slimstar2
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Re: Dual bed heaters ???? Any thoughts?

Thanks for the feedback guys. !st 5 hour print came out great .no lifting  . about to try another. i will post when done.

SD3, RAMPS 1.4, Lawsy's carriages modified by me, 2 SSRs, E3D V6, 2 Power supplies, Independent monitoring of both power supplies (amps and volts) also extruder and bed temps, Blue Tooth connectivity, bearings in all axis & rotational points, Y axis direct drive.  Remotely controlled power box on / off . Gecko Tec build plate . Renamed FrankenDoodle