software attempts to extrude before temp is reached

Hey all,

Ok I feel I am getting very close to actually printing something. But I am having a issue with the reprap program trying to extrude before the heater reaches the proper temperature. I am using a material called PPRO which when running the extruder exerciser seems to melt and extrude at 250 c. So I set the preferences on extruder_0 Extruder0_ExtrusionTemp(C) = 250 which seems logical.... i guess
also:
Extruder0_Beta(k) = 550.0
Extruder0_Capacitor(f) = 0.000003
Extruder0_Rz(ohms) = 4827
as suggested by Ian... thanks

When I tell the software to build the 10mm-cube.stl found on the website each axis goes to its home position. I then receive a message:
"Waiting For Extruder To Reach Working Temperature"
and the temp reading slowly creeps up. When it reaches only 150 it them begins to attempt to print, but of course nothing comes out because it is not hot enough yet. Any Idea on what I might be missing?

Thank you much!

250

Edited 1 time(s). Last edit at 07/22/2008 09:23PM by sid.

Hi sid,

Harmful fumes sound bad. I believe I do have a PTFE barrel on my extruder. Guess I better stop using PPRO. I found that stuff at the local plastic store I guess its used for plastic welding. I also have been using ABS a bit but that seems to need to be even hotter to melt.

Do you have any recommendations of materials that melts at a lower temperature and are readily available?

cheers!

PTFE starts to lose its mechanical strength at 250C but I don't think it gives off any fumes till at least 300C.

I don't know anything about PPRO but if it really does only melt at 250C then you will have a problem because you need to extrude well above the melting point to get the layers to bond. Twice the melting point minus ambient is a good starting point.

ABS melts at 105C and will extrude easily at 180C so I think there is something wrong with your temperature measurements.

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[www.hydraraptor.blogspot.com]

hi nophead,

thanks for the tips,

Because my extruder has not gone up in flames or even melted yet, lets assume that my temperature readings are not correct. I could not get the ABS to extrude until above 250C(inaccurate reading)on my machine. The PPRO seems to extrude at right around 230C(inaccurate reading). If I set the preferences on extruder_0 Extruder0_ExtrusionTemp(C) = 230. When I tell it to build why does the machine start the build attempting to extrude when the temp is only 150 rather then 230? Is there another setting in the extruder prefs that I need to change? Any ideas?

Also, does anyone know the melt and extrude temps for HDPE?

cheers!

I don't use the RepRap s/w so I don't really know.

HDPE melts at 130C and needs about 240C to guarantee a good bond but you can get away with 180C upwards for small objects. I.e. objects small enough to not cool back to ambient by the time you put down the next layer.

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[www.hydraraptor.blogspot.com]

dwbowen Wrote:
-------------------------------------------------------
> When I tell the software to build the
> 10mm-cube.stl found on the website each axis goes
> to its home position. I then receive a message:
> "Waiting For Extruder To Reach Working
> Temperature"
> and the temp reading slowly creeps up. When it
> reaches only 150 it them begins to attempt to
> print, but of course nothing comes out because it
> is not hot enough yet. Any Idea on what I might be
> missing?

There are some "Debug" messages in the Java code. I'm not sure how you see those messages but they may provide more information about what's going wrong.

Hey John,

A small window appears labeled progress. In this window the message:
"Waiting For Extruder To Reach Working Temperature" with a reading of the current temp. Is this what you are referring to as a debug message?

Regardless of where I set the temp at Extruder0_ExtrusionTemp(C) in preferences the program always wants to begin the build when the temp in the progress window reaches only 150. Has anyone out there experienced this problem?

cheers!

dwbowen Wrote:
-------------------------------------------------------
> A small window appears labeled progress. In this
> window the message:
> "Waiting For Extruder To Reach Working
> Temperature" with a reading of the current temp.
> Is this what you are referring to as a debug
> message?

Sprinkled around the sources are calls to "Debug.d" which appear to be displaying more detailed progress reports. For example just before moving to 0.0 and pre-heating the code says:

Debug.d("Moving to heating zone");

If you can find out how to enable those messages and where they get displayed/saved you might see a message about why the pre-heat is ending early.

Hey All,

Well I found a half @ssed way around my problem. In the extruder exerciser I noticed that when I reach the desired temp the PWM led begins to flicker. By telling the build to pause between layers I can wait until I see the flicker to begin the build. This kinda works. But it is only a temporary fix. I was able to print the first layer of the wide bar still. Where another bug showed up. At the end of the first layer when the cooling fan kicks on the x axis slowly jerks its way over continuing past the print smashing into the max x endstop. Which is odd because I thought it was an endSTOP!

So, does anyone know how to enable the debug messages that John is referring in the previous post? Or again has anyone out there experienced either of these bugs?

Here is what my extruder settings are at:

Extruder0_Address = 8
Extruder0_AngleSpeedFactor(0.1) = 0.5
Extruder0_AngleSpeedLength(mm) = 2.5
Extruder0_Beta(k) = 550.0
Extruder0_Capacitor(F) = 0.000003
Extruder0_ColourB(0..1) = 0.6
Extruder0_ColourG(0..1) = 0.3
Extruder0_ColourR(0..1) = 0.3
Extruder0_CoolingPeriod(s) = 40
Extruder0_ExtrusionDlay(ms) = 1000
Extruder0_ExtrusionHeight(mm) = 0.8
Extruder0_ExtrusionWidth(mm) = 0.7
Extruder0_ExtrusionOverRun(mm) = 120
Extruder0_ExtrusionSize(mm) = 255 'not accurate.. see previous posts'
Extruder0_InfillSpeed(0..1) = 1.0
Extruder0_MaterialType(name) = PPRO

Extruder0_MaxSpeed(0..255) = 230
Extruder0_NozzleWipeDatumX = 20
Extruder0_NozzleWipeDatumY = 12
Extruder0_NozzleWipeEnabled = false
Extruder0_NozzleWipeFreq = 4
Extruder0_NozzleWipeStroke = 15
Extruder0_Offsetmm) = 0
Extruder0_OffsetY(mm) = 0
Extruder0_OffsetZ(mm) = 0
Extruder0_OutlineSpeed(0..1) = 0.6
Extruder0_Reverse(ms) = 0
Extruder0_Rz(ohms) = 4837
Extruder0_XYSpeed(0..255) = 150
Extruder0_hb(C) = 20
Extruder0_hm(C/pwr) = 1.7
Extruder0_t0()..255) = 0

Does anyone see anything here that would cause these issues? Or have any suggestions? Even though the flickering led is a temporary fix.... at least I got something to print.... now time for beer!

cheerio!

Hi

You can set CommsDebug and Debug True in preferences.

However you are using Arduino and I don't know how helpful debug will be. Arduino is new compared to the PIC electronics and as I believe what debug tells you will be dependant on the Arduino firmware it may not be of help.

The problem you have with the endstop may be a bug in the firmware as I have seen something similar. I think the movement you see should not be happening and there fore the end stop is not being looked for. It would be useful if you run the job again and operate the end stop during moves that are part of the job and see if the end stop works then. If it doesn't there is a pretty basic bug but if it does stop movement it is clear there is a subtle bug in there somewhere.

The Arduino is definitely the future but don't forget all the software is a work in progress.

Zach has done most of the firmware and is working on a new version. The source is available and if you can follow it you may be able to help. If you find a bug and it can be confirmed by someone else send Zach a private message as I am sure he would like to hear about it.

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Regards

Ian