SoliForum - 3D Printing Community — Press Bed Heater

Re: Press Bed Heater

null@example.com (ScRamjet) — Thu, 19 May 2016 00:00:43 +0000

OK, with enough light and a magnifying lens, the FET is a FDD8876 which is supposed to do 15A continuous @ 30V.
Same part for Bed and Hot end drives.
No idea why it died. But, It can be replaced easily so I'm working that now.
Part is available at Digikey for $0.81 and Mouser for $0.83 each.
Soldering it is no issue for me.
In the meantime I'm hooking up a standard ice cube relay so I can get back to printing.
New Power Supply is here, 150W free air, 180W with a fan.

Re: Press Bed Heater

null@example.com (ScRamjet) — Sat, 14 May 2016 19:25:53 +0000

Glad to learn the stock heater wattage, New one is 132W (cant read the rating on it, just worked from amps * 24V.
And yes, I took the reading right after switching the heat on.
Since the stock supply is short on amps I'm waiting for my new one to arrive.

Question, Do you have any idea what the part is that controls the power to the bed as it seems to be dead now.
I suspect I ran it over wattage as well.
If need be I'll just research a match to the new wattage and skip the relay.

Thanks

Scramjet

Re: Press Bed Heater

null@example.com (trayracing) — Fri, 13 May 2016 01:49:44 +0000

Stock pad is 90W, so good to know what the Press power margin is.
Was your 5.5A hot or cold? If it was measured hot, it will draw more cold, putting you pretty near the rated li mit of your supply. OTOH, you're not ordering from some random ebay site, so there's a better chance your new supply will handle its rated current.

Re: Press Bed Heater

null@example.com (ScRamjet) — Thu, 12 May 2016 01:05:06 +0000

Normal clear glue seems to be holding. If it peels loose I'll re-glue with RTV copper - Recommended by a fellow local geek.

New Problem, New bed heat pad overloads the power supply after about 1/2 hour or so causing brief shutdown. Used a clamp on meter and found it's pulling 5.5Amps !!! Yipe !!!
SD brick is only good for 7.5 so add in the extruder/Hot End and I'm Waaay over power budget. No wonder the old pad took so long to heat the bed, low wattage there !
Now ordering a 150W 24V power supply from Digikey - Cheapest I found.
I'll hack into the board and feed the power through the controller. OR
If the traces look wimpy I'll add a Solid State Relay triggered by the part on the pcb. We are getting some for a design at work that will do nicely.

ScRamjet

Re: Press Bed Heater

null@example.com (trayracing) — Sun, 08 May 2016 00:59:55 +0000

If that doesn't work, (heat softens a lot of glue), the replacement pad SD sent me for mine was held on by 3M 467MP tape. (I had to search old posts for that. )
I think other some other models of 3m tape will hold it on as well.

Re: Press Bed Heater

null@example.com (ScRamjet) — Fri, 06 May 2016 22:36:11 +0000

OK, Used regular glue, Let it set up for a day, Now we see if it holds.

I can already say the bed heats MUCH faster now.
Starting Print...

Press Bed Heater

null@example.com (ScRamjet) — Fri, 06 May 2016 03:52:26 +0000

OK, so the heater died (broken wire at the heater) Soldering does not work and I'm very good at it.
Got a replacement that is slightly larger and I believe more watts.

How do I attach the new pad to the bed, Old one was sticky, new one is not.
Got it soldered into the wiring, and it heats but I can't get it to stay on the bed once I remount the bed.
I'd really like to get back to printing stuff.

Thanks
Scramjet