Problems with extrusion
Posted by NathanB
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Problems with extrusion July 08, 2011 08:21PM |
Registered: 12 years ago Posts: 38 |
So I've got my Prusa up and running now and have ran into some issues.
I'm not sure if it is a problem with the firmware or with my Skeinforge settings...
I'm running RAMPS V1.3 with Sprinter and Skeinforge 41...
The problem is that when I go to try to print something, not enough plastic comes out...
I keep changing the e_steps_per_unit in sprinter configuration.h, but I've up'ed it to around 750 now and it still doesn't output the right amount of plastic...
I'm going to attach my configuration.h file here... But I'm thinking that it might be something in Skeinforge though....
Where should I be looking?
Thanks!
I'm not sure if it is a problem with the firmware or with my Skeinforge settings...
I'm running RAMPS V1.3 with Sprinter and Skeinforge 41...
The problem is that when I go to try to print something, not enough plastic comes out...
I keep changing the e_steps_per_unit in sprinter configuration.h, but I've up'ed it to around 750 now and it still doesn't output the right amount of plastic...
I'm going to attach my configuration.h file here... But I'm thinking that it might be something in Skeinforge though....
Where should I be looking?
Thanks!
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Re: Problems with extrusion July 08, 2011 09:34PM |
Registered: 13 years ago Posts: 197 |
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Re: Problems with extrusion July 09, 2011 12:33AM |
Registered: 12 years ago Posts: 38 |
Quote
Anthong Redbeard
When you are in repsnapper can you get it to extrude at a rate you expect?
Make sure Dimension is enabled with add flowrate in skeinforge.
What material are you extruding and at what temp?
Verify your thermistor tyoe and that's the one you have set in the configuration.h firmware
I'm using Printrun from Kliment and it seems to be extruding about half of what I tell it to...
I'm using PLA at 190 degrees and am using a MakerGeat thermistor with the correct type and table in firmware...
Should I keep upp'ing the e_steps_per_unit?
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Re: Problems with extrusion July 09, 2011 04:39PM |
Registered: 15 years ago Posts: 38 |
I had to up my esteps_per_unit to about 1400 to extrude the right amount of plastic. How much filament is pulled into the extruder when you send it a command of E10? it should pull in 10mm. If its lower, like 6mm, then you need to raise the esteps. For example, if you are pulling in 6mm with your esteps set to 750, then 6/10 = 750/x. therefore your esteps should be around x = 1250. recompile your firmware and try again.
Good luck, you're almost there!
Germanicus
Good luck, you're almost there!
Germanicus
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Re: Problems with extrusion July 09, 2011 08:19PM |
Registered: 12 years ago Posts: 38 |
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Re: Problems with extrusion July 09, 2011 09:45PM |
Admin Registered: 15 years ago Posts: 1,470 |
NathanB Wrote:
-------------------------------------------------------
> Germanicus-
>
> Thanks so much! I was afraid to up the
> e_steps_per_unit that far.... the default value
> was like 16 or 32 or something... I thought
> something was wrong when I was up to 750 and it
> still wasn't right....
>
> I very much appreciate the help!
The default is the number of steps per mm of extruded plastic. The number you want is steps per mm of incoming filament, which will be much much higher.
-------------------------------------------------------
> Germanicus-
>
> Thanks so much! I was afraid to up the
> e_steps_per_unit that far.... the default value
> was like 16 or 32 or something... I thought
> something was wrong when I was up to 750 and it
> still wasn't right....
>
> I very much appreciate the help!
The default is the number of steps per mm of extruded plastic. The number you want is steps per mm of incoming filament, which will be much much higher.
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Re: Problems with extrusion July 10, 2011 06:38PM |
Registered: 13 years ago Posts: 1,780 |
There's no need to play around with e steps per mm in the firmware when you can use the filament packing density ratio in SF 40 and later versions to do the same thing. Just use the calculated steps per mm based on your extruder design in the firmware and then set the filament packing density ratio to push the correct length of the feed.
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Re: Problems with extrusion July 10, 2011 08:50PM |
Registered: 12 years ago Posts: 38 |
Okay, so I've upped the e_steps_per_unit a lot with no result... I think the problem might be with my Skeinforge settings...
Brnrd: What should I be doing to the filament packing density to up the amount of plastic being put out? Should lowering it raise the plastic output?
Everything works right... it's just not working together right...
I really don't understand what I'm doing wrong here... I've tried to tweak just about everything... Skeinforge is about the most confusing piece of software I've ever come across.... =-/
I really appreciate the help everyone!
Brnrd: What should I be doing to the filament packing density to up the amount of plastic being put out? Should lowering it raise the plastic output?
Everything works right... it's just not working together right...
I really don't understand what I'm doing wrong here... I've tried to tweak just about everything... Skeinforge is about the most confusing piece of software I've ever come across.... =-/
I really appreciate the help everyone!
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Re: Problems with extrusion July 10, 2011 09:49PM |
Registered: 13 years ago Posts: 1,780 |
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Re: Problems with extrusion July 11, 2011 05:32AM |
Registered: 12 years ago Posts: 38 |
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Re: Problems with extrusion July 11, 2011 06:58AM |
Registered: 13 years ago Posts: 1,780 |
In the long discussion in the Skeinforge forum
Set your firmware to this value. This assumes a diameter of 5 mm for your hobbed drive. If you have a caliper, you can measure the diameter of your hobbed drive and use it instead
Then, with the FPDR set to 1, measure the displacement of the filament after manually sending a command to extrude a known length (50-100). It's easier if you don't have a hot end on the extruder. Then set the FPDR to the ratio of the actual length versus the expected length.
Quote
Nophead
The steps per mm will be approximately micro steps per rev * gear ratio / ( pinch wheel diameter * pi).
For a Wades and x16 driver it would be 3200 * 39/11 / (5 * pi) = 722
Set your firmware to this value. This assumes a diameter of 5 mm for your hobbed drive. If you have a caliper, you can measure the diameter of your hobbed drive and use it instead
Then, with the FPDR set to 1, measure the displacement of the filament after manually sending a command to extrude a known length (50-100). It's easier if you don't have a hot end on the extruder. Then set the FPDR to the ratio of the actual length versus the expected length.
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Re: Problems with extrusion July 11, 2011 07:21AM |
Registered: 12 years ago Posts: 38 |
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Re: Problems with extrusion July 11, 2011 07:32AM |
Registered: 14 years ago Posts: 3,742 |
For ABS 0.86 is correct, PLA should be 1.
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
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Re: Problems with extrusion July 11, 2011 07:40AM |
Registered: 13 years ago Posts: 1,780 |
How far off is the extruded length? Make sure that you're not missing steps. You can also turn the power off the motor and turn the driven gear by hand and measure how much filament is pulled per rotation. You probably need multiple rotations to get an accurate reading. That would give you the effective circumference of your hobbed drive which you can compare to the circumference that you used in your equation. The FPDR is the ratio.
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Re: Problems with extrusion July 11, 2011 07:46AM |
Registered: 14 years ago Posts: 3,742 |
Make sure your speed is 50 to 100 mm/s and NOT 500, 1000 or more.
Over 100 mm/s you stand the chance of loosing steps.
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
Over 100 mm/s you stand the chance of loosing steps.
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
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Re: Problems with extrusion July 11, 2011 07:55AM |
Registered: 12 years ago Posts: 38 |
rhmorrison, That's under the speed tab in Skeinforge, right? If so, I'm running around 30.. Or is that in the firmware? If it is, I haven't changed it then from the default value..
brnrd: When I turn it by hand what will that tell me? Should I count the turns of the big wheel or the smaller one? Once I get a ratio of gear turns to length of extruded filament, what do I do with that?
Sorry guys... but I just can't wrap my mind around where I've went wrong...
Should I change from 1/16th to 1/8 or 1/4 instead? I understand that would change my e_steps_per_unit also, correct?... since it seems this value is off still anyhow, perhaps I should do that.... This would help if I was missing steps as well, right?
brnrd: When I turn it by hand what will that tell me? Should I count the turns of the big wheel or the smaller one? Once I get a ratio of gear turns to length of extruded filament, what do I do with that?
Sorry guys... but I just can't wrap my mind around where I've went wrong...
Should I change from 1/16th to 1/8 or 1/4 instead? I understand that would change my e_steps_per_unit also, correct?... since it seems this value is off still anyhow, perhaps I should do that.... This would help if I was missing steps as well, right?
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Re: Problems with extrusion July 11, 2011 08:02AM |
Registered: 14 years ago Posts: 3,742 |
If you are using a standard Wades with 1/16 stepping then 722 is the proper value to use for E_STEPS_PER_MM assuming you are using Skeinforge >= 40 (i.e. the last two versions).
I calibrated mine by removing the hot end and sending a G1 F10 E100 command and measuring how far the filament moved and then adjusting my E_STEPS_PER_MM (compile, upload, restart) and then do it again until an E100 moved the filament 100mm (as exact as I could measure it).
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
I calibrated mine by removing the hot end and sending a G1 F10 E100 command and measuring how far the filament moved and then adjusting my E_STEPS_PER_MM (compile, upload, restart) and then do it again until an E100 moved the filament 100mm (as exact as I could measure it).
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
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Re: Problems with extrusion July 11, 2011 08:13AM |
Registered: 12 years ago Posts: 38 |
rhmorrison, Just to be sure - you were measuring the amount of filament EXTRUDED from the machine, or the amount PULLED INTO the extruder? I ask as I know that there is a distinction somewhere - though I'm assuming that this might not be relevant as I believe it has something to do with Skeinforge...
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Re: Problems with extrusion July 11, 2011 08:23AM |
Registered: 14 years ago Posts: 3,742 |
I already stated that I REMOVE the HOT END so of course I measure the filament PULLED INTO the extruder!
YES, the RepRap Host (and Skeinforge < 40) ASSUME that E_STEPS_PER_MM is set such that G1 E1 extrudes 1mm of filament OUT of the hot end, whereas Skeinforge >= 40 ASSUMES that E_STEPS_PER_MM is set such that G1 E1 PULLS 1 mm of (1.75/3 mm filament) into the extruder!
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
YES, the RepRap Host (and Skeinforge < 40) ASSUME that E_STEPS_PER_MM is set such that G1 E1 extrudes 1mm of filament OUT of the hot end, whereas Skeinforge >= 40 ASSUMES that E_STEPS_PER_MM is set such that G1 E1 PULLS 1 mm of (1.75/3 mm filament) into the extruder!
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
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Re: Problems with extrusion July 11, 2011 08:25AM |
Registered: 14 years ago Posts: 3,742 |
Try Kliment's Pronterface, I think you will like it as a Host Software.
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
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Re: Problems with extrusion July 11, 2011 08:34AM |
Registered: 12 years ago Posts: 38 |
rhmorrison: I'm already using Pronterface, but thanks... never had any luck with reprap host software or anything else... Pronterface worked from the start.
Thanks for the help - give me 8 hours or so and I'll give this a shot tonight when I'm back from work... I really appreciate the help!
Thanks for the help - give me 8 hours or so and I'll give this a shot tonight when I'm back from work... I really appreciate the help!
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Re: Problems with extrusion July 11, 2011 02:08PM |
Registered: 13 years ago Posts: 1,780 |
As I wrote before, a lot of people ignore the Filament Packing Density Ratio (FPDR) and do everything with the E Steps per mm in the firmware. That would work too, but I think that's not as convenient as setting the steps per mm to the calculated value and then adjusting the FPDR parameter for each feed (PLA, ABS, etc) with different colors and from different vendors.
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Re: Problems with extrusion July 11, 2011 02:47PM |
Registered: 12 years ago Posts: 38 |
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Re: Problems with extrusion July 11, 2011 03:32PM |
Registered: 13 years ago Posts: 1,780 |
Yes. It's best to set it by measuring actual feed length.
FPDR = (Measured Feed Length)/(Expected Feed Length)
If you want to tweak your test print, then decrease FPDR to increase infill or filament width until you get the desired value based on the PWOT or IWOT. If you measure the extruded witdh with a caliper, then you can change the FPDR as follows:
New FPDR = Old FPDR x (Measured Width)/(Desired Width)
But make sure that you have set the feed diameter correctly.
Edited 1 time(s). Last edit at 07/11/2011 03:35PM by brnrd.
FPDR = (Measured Feed Length)/(Expected Feed Length)
If you want to tweak your test print, then decrease FPDR to increase infill or filament width until you get the desired value based on the PWOT or IWOT. If you measure the extruded witdh with a caliper, then you can change the FPDR as follows:
New FPDR = Old FPDR x (Measured Width)/(Desired Width)
But make sure that you have set the feed diameter correctly.
Edited 1 time(s). Last edit at 07/11/2011 03:35PM by brnrd.
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Re: Problems with extrusion July 13, 2011 01:37PM |
Registered: 12 years ago Posts: 38 |
It seems now like my extruder is trying to move too quickly... Its like it is spinning so fast that I think it is stripping the PLA filament and it doesn't extrude properly then... where can I turn this thing down... the axes move properly and at a fine speed, but the extruder spins like crazy... My problem now is that the hobbed bolt is stripping the filament and I'm not getting anything being pushed through...
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Re: Problems with extrusion July 13, 2011 02:21PM |
Registered: 13 years ago Posts: 1,780 |
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Re: Problems with extrusion July 13, 2011 02:42PM |
Registered: 12 years ago Posts: 38 |
No, I'm trying to print using pronterface... Thinking its firmware settings that might need changed...
Side Note: Every time I try to turn off acceleration in Sprinter by commenting out the line in configuration.h like it says, it throws a compile time error... I don't necessarily need accelleration right now... Thought it would help to turn it off, but I've been unable to thus far..
Side Note: Every time I try to turn off acceleration in Sprinter by commenting out the line in configuration.h like it says, it throws a compile time error... I don't necessarily need accelleration right now... Thought it would help to turn it off, but I've been unable to thus far..
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Re: Problems with extrusion July 13, 2011 03:00PM |
Registered: 13 years ago Posts: 1,780 |
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Re: Problems with extrusion July 13, 2011 03:05PM |
Registered: 12 years ago Posts: 38 |
I can't tell what the Pololu is set to really... The POT just spins and doesn't stop at either extreme, so I can't tell how high it is.. It works and doesn't stall or bind up, so that's good... The e_steps_per_unit is set to around 700 -which seems to be enough plastic when it comes out - but it usually strips before putting out enough...
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Re: Problems with extrusion July 13, 2011 03:32PM |
Registered: 13 years ago Posts: 1,780 |
The step size is set using the jumpers that are under the Pololu boards. If all 3 jumpers are installed, it's 1/16 steps. There's a table in the Pololu website.
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