[SOLVED] To what extent does skeinforge control the temperature?

I'm pretty new to skeinforge but I'm getting some pretty decent prints with it now. I just have a few questions left. I have a heated bed covered in kaptop tape and I've been getting really bad warping when printing large objects. I was a little surprised by this because I was under the impression that heated beds solve the warping problem. I took a random guess that maybe I didn't have the temperature high enough and changed it from 60 to 90 (printing PLA). The temp was about 83 when I started the print but by the time it failed due to warping I looked and saw that the temperature had dropped back down to 60!
So I'm wondering, to what extent does skeinforge control the temperature? I'm using Skeinforge 40 to generate gcodes and repsnapper to talk to the printer. I'm used to manually turning on the extruder and heated bed in repsnapper and telling it what temperature to use. If I don't turn on the extruder is there some command in the generated gcodes that will turn on the extruder and wait for it to heat up? Are there commands in there that are controlling my heated bed temp as well?
Thanks guys, there is a lot going on with this software I'm still wrapping my head around it.

EDIT: Marking this as solved because I feel like I now have a good understanding of how skeinforge handles temperature.

Edited 1 time(s). Last edit at 07/17/2011 11:57AM by unicoder.

I use a start code see below

My start code is
G21; metric is good
G90; absolute positioning
G92 X0 Y0 Z0 E0; zero the extruded length axes

My end code is
G91
G1 F70
G1 E-10 F30000; sucks filament back quickly to stop ooze
G1 Z7 F70; lifts nozzle 7mm from finished print surface
G1 F2300
G1 X-10 Y100 F2300; moves print bed out for easy job removal
G90
M104 S0; turns off extruder


but I do turn on the heat to the extruder in Repsnapper until it reaches temp, however I use the temp setting in SF to set the printing temperatures, I'm printing PLA at 175C. Big but though before hitting print in Repsnapper turn off the heat to the nozzle as otherwise SF and that setting cancel each other.

As for the heated bed I'm heating to around 60C and have no control over this, I just have 4X 2.2 ohm heater blocks in series hooked up to a laptop charger running at 18V 60W. I put glass on top of my heated bed and the prints stick so well I have to remove the glass and let it get completely cold before the prints pop off.

I do not use the bed temp setting in Repsnapper as my bed is Not hooked up to the Gen6 board I use

Hope this helps
Gary

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__________________________________________________________________________
Experimenting in 3D in New Zealand

Make sure that you have CHAMBER and TEMPERATURE turned on in Skeinforge. In CHAMBER, set the bed temperature to what you want.

I put several layers of cardboard UNDER my heat bed, and it helps hold temperature better, and warms up faster. Also avoid putting the printer in a drafty place. Even a person walking by can generate enough wind to warp thin walled objects.

> but I do turn on the heat to the extruder in
> Repsnapper until it reaches temp, however I use
> the temp setting in SF to set the printing
> temperatures, I'm printing PLA at 175C. Big but
> though before hitting print in Repsnapper turn off
> the heat to the nozzle as otherwise SF and that
> setting cancel each other.

? It didn't work this way for me. I turned off the heat in Repsnapper before hitting print and skeinforge didn't maintain the temperature. It dropped down to 160 and stopped melting plastic. I definitely have temperature enabled in skeinforge and all the temps are >= 190 so what gives? Are you sure it works that way? It seems to work fine for me to keep the temperature turned on in Repsnapper anyway, so I'll just keep doing that. Perhaps the difference is that I'm using a RAMPS board.

Regarding warping, thanks for the tips, jcabre. Unfortunately, I am still getting warping. I've tried turning the bed temperature all the way up to 100 C, I've got cardboard insulating it now and I even tried using a really tall skirt to prevent a draft getting in but nothing works! Large objects warp and peel off part way through the print. I thought a heated bed with kapton tape was supposed to stick to PLA, is that not true? I guess I'll have to get some glass, that's the only thing people consistently rave about.

I found it's wasn't the print not sticking to the tape it was the tape lifting from the bed which is why I went to glass, you do need to clean the glass before each print though. I just clip the glass on with bulldog clips and then wipe it with meths and toilet paper

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__________________________________________________________________________
Experimenting in 3D in New Zealand

Skeinforge does not maintain temperatures, your hardware/firmware does.
Skeinforge sends an appropriate GCode command to tell the firmware to set the extruder/bed temperature to a particular value (and keep it there).
Look at the GCode the Repsnapper created.
Look for M104, M109, M140, M141 and M230 commands.

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Alright guys, I'm at my wits' end here. I finally bit the bullet and went out and got some glass sheets and the PLA still doesn't want to stick to it! I've set the temp to 60 degrees. The thermistor is attached to the bottom of the heat bed, but I think the temp should be about the same for the glass. I even tried setting it to 80 degrees to make sure. I'm not even printing a very large object, it just doesn't want to stick to the glass at all. I'm also cleaing it carefully between prints with isopropyl alcohol. Do you guys have any ideas? Is there something I'm missing?

rhmorrison Wrote:
-------------------------------------------------------
> Skeinforge sends an appropriate GCode command to
> tell the firmware to set the extruder/bed
> temperature to a particular value (and keep it
> there).
> Look at the GCode the Repsnapper created.
> Look for M104, M109, M140, M141 and M230 commands.

But do those GCodes command the printer to wait for the temp to be correct before proceeding, or would the print just continue even though the temperature hasn't been reached yet?

See the GCodes in the wiki!

M104 - Does NOT wait
M109 - WAITS...

M140 - Does NOT wait
M141 - WAITS...

M230 - Enable/Disable Wait for Temperature change

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

M141 sets the chamber temperature and it doesn't wait.

Correct.

4.4.13 M104: Set Extruder Temperature (Fast)
4.4.14 M105: Get Extruder Temperature
4.4.18 M109: Set Extruder Temperature
4.4.31 M140: Bed Temperature (Fast)
4.4.32 M141: Chamber Temperature (Fast)

Fast means DO NOT WAIT.

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Thank you for the GCode reference! I've been wondering if there was a good reference out there. And thanks everyone for the tips on temperature.
I'm afraid that by posting twice in a row, I may have obscured the more pertinent issue I'm having.
Does anyone have any ideas why my PLA isn't sticking to glass? Every single time I've tried, the print doesn't even get halfway through when the edges start to curl and suddenly the print is sliding around on the plate (!!) with no apparent desire to stick to the glass.
This is especially frustrating and disconcerting considering:
1. In researching the problem, I see people saying everywhere that warp isn't as big of a problem with PLA as it is with ABS, so I'm losing hope of ever being able to print with ABS.
2. Everyone says that prints stick so hard to glass that you have to wait for it to cool down before you can remove the print.
This leads me to believe I must be doing something very wrong, like freezing the glass instead of heating it, or blasting it with ice cold air, or using glass with teflon coating.
Any ideas?

PLA should have stuck at the temperature range that you tried. On my set-up (glass on aluminum plate heated by Prusa PCB heatbed from the bottom with the thermistor on below the PC which sounds similar to yours, I usually set the temperature of the bed around 70-75 C for PLA .

Are you sure that you have the correct table loaded in the firmware? Perhaps you can test this by putting your thermistor in boiling water and ice.

If you have the Chamber option in Skeinforge enabled, make sure that you set the bed temperature accordingly. Preheating the glass, as I think you were doing, is a good idea.

You should also extrude the first layer at a slower feed and flow rate. I typically set my first layer between 10-20 mm/s with the flow rate scaled down accordingly. The height of the nozzle tip from the bed is also critical. Some people like to set it closer than the layer height. I usually set the first layer height to be the same as the rest.

Some people can get PLA to stick to glass at lower temperatures but I found that I needed at least 100C for the first layer (measured on the bottom surface of the glass). [hydraraptor.blogspot.com]

Also I find isopropyl leaves a white residue which reduces adhesion compared to methanol or acetone.

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[www.hydraraptor.blogspot.com]

Acetone or methanol doesn't remove grease very well. I've had success by washing the glass with a good detergent once in a while and wiping with acetone between prints.

I wipe my glass with methylated spirits and kitchen towel, now that I am sorted PLA sticks amazingly well at 60C

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__________________________________________________________________________
Experimenting in 3D in New Zealand

Doh! I think I was using the wrong temperature table. I was using the 100k one (beta 4066) that comes with the firmware, but I'm using a thermistor from ultimachine.com which needs a custom temperature table. The thermistor looks exactly like the one from makergear, I guess I just assumed they were the same. So I changed the temperature table for the bed, cranked the temperature up to 86 (that's as high as it would go!), closed all the windows, wiped it down with a dry cotton cloth (I don't have that other stuff) and tried again. I nailed the first layer and thought everything was going well until there were 5 seconds left and the print started sliding freely.
It does seem stickier, so I wonder if I just need some extra temperature and a cleaner bed. Nophead, how did you get your bed so hot? I'm using a 20 amp power supply (for the bed and the RAMPS), shouldn't that be enough or do I need a dedicated psu?
Doesn't anybody have a tried and true formula that makes things stick every time?
Btw, the thing I'm trying to print is [www.thingiverse.com]
I just noticed in the comments someone said that it would print better upside down, but it really should stick either way I think.

It sounds like your heater might be turning itself off before the print is finished. Or your part is not making enough contact with the bed.

How did you wire your heater to the RAMPS? If it's v1.2, then you need to connect the +12V (two wires to supply 10-12A) from the power supply directly to the heater. And then connect the other side of the heater to the - terminal of D8. To be safe, I also reinforced the ground connection from the MOSFET to the 3 extra pins for GND next to the RAMPS power connector. I also put a heatsink on the MOSFET to keep it cool to the touch.

If you have 1.3, then connect your heater wires directly to the MOSFET terminals and make sure to supply the additional power using 2 x +12V wires and 2x GND wires from the PSU.

Quote

Nophead, how did you get your bed so hot?

I used AL clad resistors powered from the mains.

I do have a Prusa PCB heater that I have tested but it struggles to get hot enough for ABS. It should easily get to 100C though.

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[www.hydraraptor.blogspot.com]

I had a similar result with the Prusa PCB heater not being able to go past 120C. I was only able to go about 90-95C above ambient temperature. I finally put the Mendel in a box and now it's able to regulate 130C with the box around 45C.

brnrd Wrote:
-------------------------------------------------------
> It sounds like your heater might be turning itself
> off before the print is finished.

I don't think so, it was still on at 86 degrees at the end of the print.

> Or your part is
> not making enough contact with the bed.

What do you mean by this? If it's as sticky as I here it shouldn't need much contact and like I said I had a solid first layer.

> How did you wire your heater to the RAMPS? If it's
> v1.2,

it is

> then you need to connect the +12V (two wires
> to supply 10-12A) from the power supply directly
> to the heater. And then connect the other side of
> the heater to the - terminal of D8. To be safe, I
> also reinforced the ground connection from the
> MOSFET to the 3 extra pins for GND next to the
> RAMPS power connector. I also put a heatsink on
> the MOSFET to keep it cool to the touch.

This is the first time I ever heard about using two wires to supply power. I went ahead and added a second wire (well, I just split the one wire to connect to two V+), but it still heats up very slow (haven't timed it, something like 45-60 minutes) and won't go over 86 (usually settles in around 84). I didn't reinforce the ground connection from the MOSFET because I'm a bit unclear on how (I found the 3 extra GND pins, but where exactly did you connect them to the MOSFET?) and I'm not that great of a solderer. Any idea why I'm not getting the extra heat? There aren't two places to connect power to the board are there? I've just got one wire for + and one for -.

> I had a similar result with the Prusa PCB heater
> not being able to go past 120C. I was only able to
> go about 90-95C above ambient temperature. I
> finally put the Mendel in a box and now it's able
> to regulate 130C with the box around 45C.

I would love to do this and make it kind of a "MakerPrusaBot". Can you give more details on your set up? Do you simply place a cardboard box upside down over the printer and remove it when you need access or did you cut windows in it?

You know, watching this print, I notice that the edges of the corners on the top few layers curl up really hard. Then when the extruder is going around the perimeter and hits those corners, it probably isn't good for the seal on the glass. I was thinking that if the layers printed quicker there would be less time for the top layers to cool and curl up. I'm going to try printing at a faster speed.

I just took a box that was big enough, turned it sideways and put the Mendel inside it so that the opening serves as a door. This gives me a chance to see how much it improves the printed parts while I make a more permanent solution. I've printed a couple of large parts and the parts stuck to the bed much better and there's much less curling. Unfortunately, I still seem some layers separating although not as bad as before.

As far as wiring the heater, go to the RAMPS wiki and scroll down about halfway to see the figure showing how to wire the RAMPS with a heated bed. This is the same wiring that I used except I used two wires from the ATX power supply to the heated bed and to the RAMPS ground as I wrote earlier. I don't think one wire would supply enough current. Other people don't reinforce the ground trace from the MOSFET so you can probably get away without doing that.

What are you using for a heated bed? Perhaps your resistance is too high.

Also, how big is the part that you're printing? Perhaps you can post a picture or a link to the stl file for others to see.

Quote
unicoder
brnrd Wrote:
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> Or your part is
> not making enough contact with the bed.

What do you mean by this? If it's as sticky as I here it shouldn't need much contact and like I said I had a solid first layer.

If the bottom of your part has a small cross-section, it might not stick very well and it can easily come off while it's still printing specially if the corners are curling up.

Edited 1 time(s). Last edit at 07/13/2011 05:12AM by brnrd.

brnrd Wrote:
-------------------------------------------------------
> As far as wiring the heater, go to the RAMPS wiki
> and scroll down about halfway to see the figure
> showing how to wire the RAMPS with a heated bed.

I'm going to assume you meant to link here

Lol! Yes.

I run 4 x 2.2 ohm heater blocks from Mendel parts using a universal laptop charger 60watt at 12Volts attached to a 5mm aluminium bed and then use standard 3mm picture frame glass on top, held in place with bulldog clips. I just give the bed 10 minutes to heat up then start printing. My objects stick so well I have to remove the glass and let it get cold, you can hear the print slowly coming free as the glass cools. I only wipe with methylated spirit because that was all I could find in the garage at the time, it does seem to do the trick though removing any greasy finger prints.

The heater blocks are bolted to the bed and have thermal paste between them and the bed

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__________________________________________________________________________
Experimenting in 3D in New Zealand

Have you measured the 12V rail at the PSU and how much is actually getting to the bed? Since power is proportional to voltage squared, any small reduction will drop the temperature. For example, I tested my Prusa heater with a bench PSU with 24/0.2 wires about 1m long. They lost about 1V, which reduces the power by 16%.

A PC PSU will tend to give less than 12V when the 12V rail is heavily loaded and the 5V rail isn't. If you see the rail is low you might need to add more load on the 5V and possibly 3.3V rails to get the 12V higher.

---

[www.hydraraptor.blogspot.com]

brnrd Wrote:
-------------------------------------------------------
> As far as wiring the heater, go to the RAMPS wiki
> and scroll down about halfway to see the figure
> showing how to wire the RAMPS with a heated bed.
> This is the same wiring that I used except I used
> two wires from the ATX power supply to the heated
> bed and to the RAMPS ground as I wrote earlier. I
> don't think one wire would supply enough current.
> Other people don't reinforce the ground trace from
> the MOSFET so you can probably get away without
> doing that.

I went ahead and wired in a second wire this morning and it heated up to 108 degrees in 10 minutes! I didn't have a lot of time so I just started a print on the kaptop tape at this point. It failed just like all the others unfortunately. Not sticky at all. My skeinforge profile is set to keep the temperature high the whole print. Is it important to lower the temp down to 60 after the print starts?

> What are you using for a heated bed? Perhaps your
> resistance is too high.

I'm using a Prusa PCB Heater.

> Also, how big is the part that you're printing?
> Perhaps you can post a picture or a link to the
> stl file for others to see.

As I mentioned, I'm printing this. I'm also testing with the iphone speak stand part of the meg-i-phone thing. That's what I tried that failed this morning.

> If the bottom of your part has a small
> cross-section, it might not stick very well and it
> can easily come off while it's still printing
> specially if the corners are curling up.

Both parts don't have much stuff touching the bed, but I still think these are great parts to test with because I want to know this will work with difficult parts as well, you know?
BTW, I quadrupled my printing speed (I'm at 200mm/s) and now I'm getting much less of a problem with corners curling up. I'm thinking we need a new "Hurry" skeinforge plugin that's kind of the opposite to cool. It makes sure that each layer goes as fast as necessary to finish before the corners start curling up

I will have to try again with fresh clean glass this evening and skeinforge settings that let the bed slowly cool back down to 60-65

For ABS on Kapton, you need to keep the temperature at 110 or above or it would come off easily. What do you have on top of the Prusa PCB heater? Did you just put kapton on top of it? Or do you have an aluminum or glass plate with Kapton tape on top? If it's glass, then I don't think 10 minutes will be enough to reach temperature. It might not even be enough for Aluminum.

Have you measured the thickness of the first layer? If you turn on the skirt option, the you can measure the thickness of the skirt and make sure that it's equal or less than the desired layer thickness.

You also have to print the first layer slower than the rest. Start with 10 mm/s for the first layer. I think 100 mm/s is too fast for RAMPS and Sprinter and leads to segment pause. A maximum of 40 mm/s should be fine. Anyway, speeding up your print is not going to prevent curling. It is minimized if your parts stick to the bed. Heating the bed helps and so does raising the surrounding temperature by putting the Mendel in a box for example.

brnrd Wrote:
-------------------------------------------------------
> For ABS on Kapton, you need to keep the
> temperature at 110 or above or it would come off
> easily. What do you have on top of the Prusa PCB
> heater? Did you just put kapton on top of it? Or
> do you have an aluminum or glass plate with Kapton
> tape on top? If it's glass, then I don't think 10
> minutes will be enough to reach temperature. It
> might not even be enough for Aluminum.

I have kapton tape directly on the heatbed that I started out printing with before I got the glass. I just set the glass directly on the heatbed (which still has the tape on it). I had taken the glass off last night and I was in a hurry so I didn't put it back on before printing, I just printed directly on the heated bed. What's the purpose of the aluminum?

> Have you measured the thickness of the first
> layer? If you turn on the skirt option, the you
> can measure the thickness of the skirt and make
> sure that it's equal or less than the desired
> layer thickness.

I don't have a tool with the accuracy necessary for that. I guess I would need some digital calipers? And what would you do if it's not the right thickness? Turn down the E_STEPS_PER_MM?

> You also have to print the first layer slower than
> the rest. Start with 10 mm/s for the first layer.
> I think 100 mm/s is too fast for RAMPS and
> Sprinter and leads to segment pause. A maximum of
> 40 mm/s should be fine. Anyway, speeding up your
> print is not going to prevent curling. It is
> minimized if your parts stick to the bed. Heating
> the bed helps and so does raising the surrounding
> temperature by putting the Mendel in a box for
> example.

I went home at lunch and finally got the speaker stand to stick! I heated the bed up to 102 degrees and let it cool to 65 degrees as it went. It wasn't stuck too hard, though. I imagine that's probably because my temperature wasn't high enough and my first layer wasn't solid enough. I will slow down the first layer and see if that helps. I'm getting SO close! My prints look REALLY good now, except for some blobs here and there. About the box, some of the plastic on my printer is PLA. If I put it in a box will the ambient temperature increase enough to soften the PLA? Have you measured it?
Thanks so much for all the help!

Back to the original topic of the post: I'd like it if I didn't have to do anything manually (in the software) when I print. If I put "M230 S0" in my start.gcode, the G-Code wiki page says that will "Enable wait for temperature change". Does that mean I wouldn't need to turn on the bed and extruder in RepSnapper. I guess there's only one way to find out...