Speed

I'm trying to increase my printing speed.

Right now I'm printing at about 20mm/s for most things, with first layer and outer perimeters at 50% of that.

Trying to increase even a small amount leads to my extruder slipping and making grinding noises on my filament while the print has gaps like this: [imgur.com]

Even at 20mm/s I see bands of light and dark like in the image above, although I don't hear the extruder slipping.

20mm/s is pretty slow, right? What's the issue here?

Things to try:

* Increasing tension on the guilder.
* Increasing hotend temperature (go up in 5 degree increments to see if it improves the situation).
* Increasing the vref on the extruder stepper driver (check to see if it's correct first - you'll need a multimeter for this. Instructions on the reprap wiki [reprap.org].

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20mm/sec is very slow.
My slow setting is 40mm/sec and I can go upwards of 70-80mm/sec depending on the part.

I wish I knew how to get those kinds of speeds. This is a delta printer, so it should be capable, right? I'm using an airtripper bowden extruder and a Pico all-metal hotend.

I'm already printing very hot, so maybe the issue is with the bowden extruder.


I was able to print at a lower temperature after tightening the idler on my extruder. It helped with some of the PLA warping issues I was having...next I'll check if it helps with the speed.

Edited 2 time(s). Last edit at 11/27/2014 08:19PM by mk3a.

The allowable speed depends of the machine you own and the overall quality you want to reach. I guess the minima for a lower range printer is 30mm.s for perimeters and 60mm.s for infill. Some people doubles that performance, and even better, but my machine can't. It looks like your printer's firmware is not set well. Check it out. And then refer to a good troubleshooting guide.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

mk3a,
I ran into all kinds of issues with my extruder and hot end (since I designed and built both). A few thoughts.

1. Check the extruder drive gear, does it have filament swarf stuck in the teeth?
2. "Grinding" sound does not sound like the driver is doing a thermal reset. If it was you could pull on the filament lightly when that happened and it would pull out.
3. Put marks on the filament with a pen, and across the end of the drive gear. Then watch both while its making that grinding noise to confirm it's the filament slipping.
4. Make sure you have a flat ground on the stepper drive shaft, it could be slipping.
5. PLA is often rougher than ABS - you can lubricate it by moistening a bit of fuzzy cloth lightly with oil (like canola even) and zip-tie it around the filament just before it goes into the extruder motor. This will also clean the filament.
6. Increase tension on the pinch roller a lot
7. The PLA may be sticking in your hot end. When it pulls back during retraction liquefied PLA can stick to the walls of the extruder and jam it, or a softened bit of PLA will mushroom and jam. Make sure there is good cooling above the hot end.
8. Critical test: try pushing the filament by hand into the hot end. Try pushing it slowly and pause, retract, push faster. Does it suddenly get very hard? Can others print PLA reliably with that hot end?

I found I could not print PLA reliably with my hot end, so I switched to ABS.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

Paul,

Thanks for the advice. Here's what I know:

1. Check the extruder drive gear, does it have filament swarf stuck in the teeth?

Possibly some. It's hard to tell.


2. "Grinding" sound does not sound like the driver is doing a thermal reset. If it was you could pull on the filament lightly when that happened and it would pull out.

Filament doesn't move when I pull during the grinding. Tried this earlier. I've adjusted the voltage to my extruder stepper and I believe it is set correctly. The grinding can start almost immediately even on a small print, so I wouldn't think it is thermal.


3. Put marks on the filament with a pen, and across the end of the drive gear. Then watch both while its making that grinding noise to confirm it's the filament slipping.

Can't do this right now, as I have my extruder disassembled. Will try later.


4. Make sure you have a flat ground on the stepper drive shaft, it could be slipping.

Checked and the gear is OK. It isn't slipping on the shaft (I had this problem some time ago and resolved it).


5. PLA is often rougher than ABS - you can lubricate it by moistening a bit of fuzzy cloth lightly with oil (like canola even) and zip-tie it around the filament just before it goes into the extruder motor. This will also clean the filament.

I have tried this in the past with another hotend to resolve jamming issues, but haven't had any jamming issues with this new one, so I have not tried it recently.


6. Increase tension on the pinch roller a lot

Tried this. I have an airtripper bowden extruder which uses a bit of diesel hose as a spring tensioner for the idler. I found it being crushed with the tension I was applying so I filled the interior of the hose with silicone caulk to make it stiffer. Even with this alteration and increased tension, the problem remains.


7. The PLA may be sticking in your hot end. When it pulls back during retraction liquefied PLA can stick to the walls of the extruder and jam it, or a softened bit of PLA will mushroom and jam. Make sure there is good cooling above the hot end.

I have good cooling on the upper part of the hotend.



8. Critical test: try pushing the filament by hand into the hot end. Try pushing it slowly and pause, retract, push faster. Does it suddenly get very hard? Can others print PLA reliably with that hot end?

I have no trouble moving the filament by hand even after a retraction. I actually have no retraction configured in my slicer, so it shouldnt be an issue right now. The hotend is the all-metal Pico from B3 innovations. I've read that some peole have had jamming issues with PLA resolved by using canola oil on the filament, but I have not had any jamming issues with it at all. I know if I increase the temperature and keep the speed low, it prints just fine, but that leads to warping issues and long print times, thus the current investigation into why I cannot print faster.

Edit: I wanted to add that I am using a 0.4mm nozzle on my hotend. I've read that the opening size can affect maximum speed, but I'm not sure how much.

Edited 1 time(s). Last edit at 11/28/2014 05:41PM by mk3a.

Hmmm.. So you can push filament by hand through the bowden tube and it never hangs up that way?

BTW, .4mm is not small, that should not be a factor.

Can you upload a video of it when it's grinding?

Feeding it by hand works fine. I will try to upload a video when I can.

Has it printed OK before?
If so, there may be a clog in the hot end.

Have you calibrated the flow rate?

I've never been able to print faster than ~20mm/s. I have calibrated my extruder steps in the Marlin firmware. My slicer settings have an extrusion multipler of 1.

I don't see how it could be clogged. It will print; it just won't print quickly.

I suspect a problem with the bowden extruder, not the hot end. Maybe I will disassemble the hot end just to have a look and make sure.

Edited 1 time(s). Last edit at 11/29/2014 12:26AM by mk3a.

Quote
mk3a
I've never been able to print faster than ~20mm/s. I have calibrated my extruder steps in the Marlin firmware. My slicer settings have an extrusion multipler of 1.

I don't see how it could be clogged. It will print; it just won't print quickly.

I suspect a problem with the bowden extruder, not the hot end. Maybe I will disassemble the hot end just to have a look and make sure.

You say you have an Airtripper what motor is on that and which drive gear this is what I believe is critical in getting this to work.

see Airtrippers V3 Extruder

Sounds like you need high torque motors for these to work effectively.

I will watch this thread carefully to see how you get on as I am considering Airtripper's for my in progress 4 head printer.

Doug

Quote
dougal1957
You say you have an Airtripper what motor is on that and which drive gear this is what I believe is critical in getting this to work.

see Airtrippers V3 Extruder

Sounds like you need high torque motors for these to work effectively.

I will watch this thread carefully to see how you get on as I am considering Airtripper's for my in progress 4 head printer.

Doug

The motor is: [www.kysanelectronics.com]

The drive gear is MK7.

Here is where I got it: [www.ebay.com]


How much does layer height affect speed? I'm printing at 0.2 mm/layer.

Edited 1 time(s). Last edit at 11/29/2014 11:06AM by mk3a.

Quote
mk3a

Quote
dougal1957
You say you have an Airtripper what motor is on that and which drive gear this is what I believe is critical in getting this to work.

see Airtrippers V3 Extruder

Sounds like you need high torque motors for these to work effectively.

I will watch this thread carefully to see how you get on as I am considering Airtripper's for my in progress 4 head printer.

Doug

The motor is: [www.kysanelectronics.com]

The drive gear is MK7.

Here is where I got it: [www.ebay.com]


How much does layer height affect speed? I'm printing at 0.2 mm/layer.

I also print at 0.2 mm layer height and can go to 60mm/s with my PrusaI3 (Printer is the limiting factor I think) I routinely print at 50 mm/s with good results but I am not using Bowden yet (I will need to on the new build)

What Hot end are you using everything I read on Airtrippers page suggests that with your setup it should be fine and if not to start looking towards the Hot End.

HTH Doug

Quote
dougal1957

What Hot end are you using everything I read on Airtrippers page suggests that with your setup it should be fine and if not to start looking towards the Hot End.

HTH Doug

Pico from B3 Innovations - [www.b3innovations.com]

I really like it. The only way I can imagine it being the problem would be if it requires more force than most to push the filament through, perhaps because it truly is all-metal: It does not have a ptfe liner like some other 'all-metal' hotends, allowing it to go all the way to 500C for printing more exotic materials like Nylon. It has never jammed on me with ABS or PLA.

Quote
Paul Wanamaker
[*] Put marks on the filament with a pen, and across the end of the drive gear. Then watch both while its making that grinding noise to confirm it's the filament slipping.

I finally got around to trying this...It's the gear/motor moving backwards when it makes the noise. Why does this happen?

I've seen something like this.

Are you using Slic3r? If so, do you have the "Wipe while retracting" setting on? If so - turn it off and see.

That's under Printer settings, Extruder1, "Wipe while retracting".

When I had it on: retraction made odd sounds and took longer.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

I am using Slic3r, but not using retraction and that box is not checked.

I believe my extruder's motor just doesn't have the torque needed and is slipping backward when it tries to extrude. I have another motor which has a planetary gear assembly which I beleive would give it more torque, but it doesn't fit my extruder parts. I'd have to design and print new parts to fit it. I may do that, but first I'm going to try stepping up the current to my extruder.

Haha, I turned up the current and a lot of the problem went away. I did away with the multimeter and just adjusted it until the print got better. :p

Excellent.
Just check that the motor doesn't get too hot. You can always put a fan on it if needed.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

20 mm/s is super slow, so slow I will go crazy (however acceptable speed when printing with rubber...)

Try to heat up the extrusion five degree more, also make sure that the xyz bearing is oiled and maintenanced.

Test if this happens with other slicer softwares.

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My tips:

The Pico has a pretty nice design overall I don't think that is what is causing this. The issue sounds like it is from the extruder motor not having enough torq. Things i would check also:
Make sure your tubing is PTFE or teflon based for maximum slipage.
increase the tension on the idler.
If you are using 3mm filament this may be the issue because 3mm filament is tough to push through a bowden setup at least in my experience.

Hope it helps