reprap mendel prusa i2 heated bed , extruder problem

hii everyone

Recently i have finished to assemble the printer and to install all needed software for reprap mendel prusa i2 .

i have encounter main 2 problems :


1.heated bed does not reach 110C degrees ( ABS ) after 20 minutes it reach 40C.

DATA :
ATX PS input on the 5V 11A circuit i measured 4.95V.
on the PWM output to the heated bed i measured 4.8V .
on the heated bed poles i measured 4.75V

i tried to keep law resistance so i ued thick wires , maybe 10-12 AWG.

what should i do to solve the problem ?



2. I have abs filament 1.75mm, the hot end reach the 230C degrees , but the extruder does not extrude continuously.

Have you put load/resistor on the 5v line as most instructions on using atx power supplies state?
Without this the power supply will be unstable.
[reprap.org]

You are using the 12v yellow supply arnt you?
The bed needs 12v to heat and so does the extruder.

Also has your psu got 2 rails for 12v.
Usually 12v on the mainboard connector is a seperate regulator to the 12v on the graphics card power connector(4 pin plug).
So use one for the bed and one for the extruder/controller supply.

Gordon

Edited 1 time(s). Last edit at 10/22/2014 06:08PM by gordonendersby.

thank you for helping .

i didnt put a load / resistor on the input 5V voltage ' should i do that ?

i also use 12V yellow and black wires /
but i thought that this 12V is for the motorsand etc /
and the 5V is for the heated bed.
i use the molex 4 pin only (pairs of 2 yellow and black wires ) to extract the 12V ' what should i do Beyond?

in addition i would be glad if you regurd my second problem /

thank you
shay v

Yes, put a load resistor on the power supply as Gordon stated - say 5W or some other load.
You cant use 5v on the RAMPS power inputs - they are both 12v.

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Waitaki 3D Printer

Just follow the instructions on the link to the wiki i gave you.
It will tell you what each wire is for including the switched line to turn on the psu.

The resistor doesnt go on any input.
It just goes between one of the 5v lines from the psu to earth.
Values in the wiki.

Both power inputs for bed, extruder, motors and controller are 12v directly from the psu.
As i said take one from each 12v source on the psu.

You can use some of the other wires for things like fans to cool the controller or for airflow over the print.
Im using one 5v supply to run my webcam so i can check the print is going well from elsewhere in the house.

Have a good read through the wiki theres lots of info there.

Gordon