ABS help

Hi,

Try several times to print ABS but fail. I wait for 1 hour and the bed only keep constantly 95 degree and the red LED never goes off, thats means the bed is at its full power.
I try to click SD print and it shows disconnected . I press connect again and keep waiting for " connecting........." for 20 minute and nothing happen. ( my Ormerod keep randomly disconnected during print since day one, a lot of wasted print )

I need to print some ABS parts for my customer. anyone who successfully print ABS please help !


Ew

Same issue, wires are too thin to the heater bed, you will see quite a big voltage difference between the bed and the psu. Add some thicker wire in parallel to the current wires to the heater bed and you should be good to go.

Dieter

#257

There are a number of threads about ABS printing such as [forums.reprap.org]. The most important aspects appear to be:

1. The supplied ATX PSUs provide somewhat less than 12V under the load of the bed heater. The Alpine PSU I received would get the bed up to 120C as reported by pre-0.53 firmware in about half an hour. I have the impression that the Ace PSU is worse. I am currently using a Corsair CX430M which holds its voltage much better than the Alpine did. I have just commanded it to 120C and I'll measure how long it takes to get there (I'll add the results at the bottom of this post). Another option is to buy a 12V 20A or 25A industrial-type PSU (£21-80 on eBay UK) and adjust it up to 13V.

2. The supplied PLA parts are not good enough for long-term printing of ABS, so the first things you print in ABS should be the nozzle mount and x-carriage. Also, raise the X-axis high while you are preheating the bed, to reduce the exposure of those parts to high temperatures.

My Corsair PSU behaves as follows (temperatures measured using 0.57a firmware):

Room temp about 20C
95C after 11 min
100C after 13 min
105C after 15 min
110C after 19 min
115C after 24 min
120C after 30 min

Edited 5 time(s). Last edit at 01/23/2014 08:40AM by dc42.

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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].

Ew - My bed only reaches around 100 (depending on ambient conditions) - I set it to 120 and leave it to get up to what it can before i start printing, then I drop the bed temp to around 90 at the start of the print and I don't have any real problems.

Is yours not printing because it is waiting for the set bed temperature to be reached? If so drop the set temperature to one it can reach (eg 95) and see how it goes...

I don't set temperatures in slic3r, just in case I want to try out different settings, or even different plastics with a particular slicing, and just enter them manually before a run.

Ray

Hot Bed Issues:-
If you are ok with electrical stuff, and not the type that cuts down 6" nails for fuses then here's a suggestion....(I'm teasing)
Use the Hot Bed Duet connections as a switching source for a relay. (I haven't looked in to it enough, but could if enough people
would like me to). Then use the relay (with a fuse in circuit) to switch thicker gauge wires between the Hot Bed and the main 12V supply, so by-passing the Duet board. (If you do go down this road, ensure you use a good quality MUTI strand cable i.e. flexible cable). While I wouldn't say people are wrong about the power supply voltage drop, I wouldn't be at all surprised if the problem is the fact there is to much 'current' whizzing through the duet board.
I haven't looked in to it as I've only just started 3D printing, and am stuck onboard ship with my printer at the moment and limited resources. But I've had similar problems arise on other PCB switch, both at work, and at home.
If you think about it, the copper tracks on the board, while quite big, aren't as robust as decent bit of cable.
To make it handle the current the board would need to be bigger for the tracks to be wider to increase the cross sectional area, and size is an issue here. (Stop giggling you in the back there ).
Cabling for higher currents is normally copper, and the cross sectional area of the cable denotes the amount of power it can handle.
My suggestion is, the next time you try to use ABS, have a feel of the ribbon cable to see if it's warm ( away from the bed connection that is, as you might just feel the conduction of the heat down the cable). Then with the back cover off the controller box, feel the board gently to see if that's warm. Heat with be generated in the bottleneck that's causing the problem.
People ok with multi-meters can search around to see where the voltage drop is highest in their systems. Just never test using the Resistance or the Current unless you know what your doing (i.e. you can fry your board if you mess up so don't unless you know what your doing).
If need be a bigger box could be printed to house a Hot Bed relay if you did decide to go down that road. And it would be close to the power connector so an idle position.

I'm not saying that the power supply isn't the problem, just would like to see the effects with my own eyes with my decent meters at home.

Hope this might have given people some ideas.
Kim..

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KimBrown
Hot Bed Issues:-
If you are ok with electrical stuff, and not the type that cuts down 6" nails for fuses then here's a suggestion....(I'm teasing)

Amazing....Love it.... I'll send that off to our Tech. Sup ashore in a minute....

Scary ! haha ! but anyway , thanks guys for all precious suggestions, I'll try to print again, but need to solve my Mac problem first, Mac seems unstable running Pronterface, ( although I can use others software ) I'm thinking of buy a new computer install with ubuntu for just printing 3D now......

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dmould

Quote
KimBrown
Hot Bed Issues:-
If you are ok with electrical stuff, and not the type that cuts down 6" nails for fuses then here's a suggestion....(I'm teasing)

Quote
KimBrown
I wouldn't be at all surprised if the problem is the fact there is to much 'current' whizzing through the duet board.

Actually, only about 50mV is lost in the Duet board, and most of that is in the mosfet. There are much bigger voltage drops in the cables. See [forums.reprap.org] and [forums.reprap.org] for a breakdown of where the voltage is lost.

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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].

Quote
KimBrown
(If you do go down this road, ensure you use a good quality MUTI strand cable i.e. flexible cable.

Kim
I am going down this road to replace the ribbon cable with some larger cross section cables. I am currently printing out a drag chain to lay the wires in so they lie neatly under the table and don't offend my eye like the ribbon cable does. Do you have a spec ( cross section/strands etc) RS etc part number that you think would be appropriate. Probably use multiple wires to increase the flexibility.
I also like your idea of using a relay to switch the power to the bed. Presumably this could allow you to use a higher voltage from a second/ replacement psu to shorten the heating time of the bed.
John

I looked into this before and decided that 3 pieces of 55/0.1 wire in parallel would work well. Total 8 wires in the chain including the thermistor wires.

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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].