The filament feed on my printer is inconsistent. At first it would not feed at all until I backed off the tension screw completely and now it feeds for some of the time but occasionally the feed stops with the motor switching backward and forwards very quickly and requires a gentle push on the large gear to get it moving again. This is not in a filament retraction stage that occurs during position changes. The problem is typical of a stepper motor that is under too much load so I would like to know of solution please.
That’s a symptom typical for the two gears being to close together.
Loosen the three screws holding the extruder stepper motor and gently move it to the left, so that the distance between the two gear’s axes will be slightly increased.
[quote=“clm”]That’s a symptom typical for the two gears being to close together.
Loosen the three screws holding the extruder stepper motor and gently move it to the left, so that the distance between the two gear’s axes will be slightly increased.[/quote]
I had already checked gear clearance and this is not the problem but it does appear to be related to the filament clamp spring tension, pointing to not enough motor torque. Unfortunately, my butterfly screw is wound fully out, so I want to know if there is an electronic adjustment for the motor and, if so, what is adjusted and to what value i.e. is it the 425mV figure that should be changed?
I had the same problem when first building my printer. The spring is what helps the gear pull the filament in, so it can not be too loose. Actually it needs to be quite tight, but not not to the point that you can’t move it anymore. You will need to find the right tension.
(And the gears should not be too close together, but this is probably not the cause)
[quote=“VEL448”]I had the same problem when first building my printer. The spring is what helps the gear pull the filament in, so it can not be too loose. Actually it needs to be quite tight, but not not to the point that you can’t move it anymore. You will need to find the right tension.
(And the gears should not be too close together, but this is probably not the cause)[/quote]
I re-assembled the filament feed (no problems found) and used a very small amount of non-creep grease on the gear-teeth and all seems well now.
I have the same issue - I can’t seem to get the filament to grip when feeding it into the extruder for the first time.
I’ve tried changing the butterfly to all possible ranges but it’s still not gripping.
should I start taking it apart?
[quote=“garethhewitt”]I have the same issue - I can’t seem to get the filament to grip when feeding it into the extruder for the first time.
I’ve tried changing the butterfly to all possible ranges but it’s still not gripping.
should I start taking it apart?[/quote]
Quite often this is due to the filament catching on edges in the pathway to the extruder but it can also be caused by the end of the filament being distorted or enlarged as will happen if it has previously been in the extruder and changed. I suggest that you straighten the filament and cut off any distorted bits at an angle to help. Also, you must hand feed first by slackening off the spring and holding the gripper open, I use a piece of filament to wedge it open while I push the filament in; you should find that you can push the filament in a long way (almost the distance from the input hole to the hot end) before re-engaging the gripper. If starting from cold with no filament in the machine I always heat the extruder for a few minutes to ensure that the filament displaces any left in the hot end; if you are changing from hot then this is not an issue but keep the heat on. Don’t forget to re-tighten the grip!
Mike.
I have the same issue as well.
Increasing the reference voltage to 0.55 had no effect.
I increased the layer size and moved the gears farther apart and the issue went away. Not sure which one fixed it but it only seemed to happen when trying to lay down thin layers. I have a feeling 0.25mm (the default it seems, in the pla_standard_new config) is too thin for this printer to handle. I increased it to 0.4mm.
I wonder if increasing the heater temperature might melt the PLA a bit faster and allow for easier feed at lower speeds.
I think a different gear ratio might be required to give a bit more torque to the feeder and lessen the strain on the motor.
Has there been a real fix for this issue? Maybe a newer motor with more torque?
I too am having feeding problems. It seems to get “caught” on something and then keeps going…repeat. The gears are not too close, gears are clean, the filament is not “bulging”, I loosened the hobbed bolt nut so it’s not too tight, and I increased the voltage.
I removed the filament just to remove the filament as an issue. When I manually have it “feed”(nothing) it doesn’t take much to stop the motor. Do motors start going bad slowly and lose strength/torque? Another question I have is the wiring. Is it possible that the wiring to that motor(and the rest for that matter) is too small of a diameter? That the motors are not getting enough Amperage through the wires?
Since the motors are current controlled and not voltage controlled, the wiring does not really influence the torque.
Make sure temperatures are correct, that hobbed bolt grips the filament correctly and that the nozzle is not clogged.
Are you using Velleman PLA?
I’ve been printing 0.2mm with no feed related problems.
[quote]I wonder if increasing the heater temperature might melt the PLA a bit faster and allow for easier feed at lower speeds.
I think a different gear ratio might be required to give a bit more torque to the feeder and lessen the strain on the motor.[/quote]
I keep having to say this.
Measure your extruder temperature with an independent instrument. My hot end was running 20 degrees hotter than the displayed temperature, yours might be running 20 degrees cooler. I generated a new thermistor table.
Having said that I was trying out a Colorfabb_XT sample I picked up at TCT, but I thought it was another filament as was running nearly 40 degrees too cool. The prints were a disaster, but the feed was fine.
You may also want to check that the nut on the hobbit bolt is not to tight.
You can set the reference voltage to 0.55 as well
This Hobbit bolt?
That’s funny.
Wow! I don’t know if I am amused or absolutely annoyed. I think I am more amazed at the people quick to comment and not actually read the post they are commenting on. If the people that commented on my post would have actually read it in it’s entirety I’m sure they wouldn’t have even commented.
These are my exact words “I loosened the hobbed bolt nut so it’s not too tight” and the response I get is “You may also want to check that the nut on the hobbit bolt is not to tight.”. Did you even read the post?
Then I said “and I increased the voltage.” and I get a response of “You can set the reference voltage to 0.55 as well”, that one might get away with it because I did not specify the .55 voltage. Although if you read the Velleman specifications to the highest voltage you should increase it to is .55, you would have known that already…if you didn’t, you shouldn’t even be replying.
Then I said “I removed the filament just to remove the filament as an issue.” ([size=150]meaning THERE. IS. NO. FILAMENT. IN. THE. EXTRUDER. TO. WORRY. ABOUT.[/size]) and you all talk about the hotend being too cold, or the hobbed bolt(NOT HOBBIT BOLT NUT) being too tight. THERE IS NOT FILAMENT GOING INTO THE EXTRUDER AT THIS POINT. IT HAS NOTHING TO DO WITH TEMPERATURE, OR FEEDING ISSUE.
[color=#FF0000]To help those who don’t read posts in there entirety, pretend you just build your K8200 and you have ZERO, NONE, NO filament going into the machine. Now you are testing your machine for the very first time and you come to testing your extruder motor for the first time. You open Repetier and tell it to extrude (input number here) let’s say 100 for giggles. While it is running you simply put your finger on the big gear very gently and the motor stops[/color]. WHY WOULD THAT BE???
Now the Velleman “tech”. When you say “the wiring does not REALLY influence the torque”, you leave yourself open for some serious scrutiny.
The SI unit for measuring an electric CURRENT is the AMPERE. Wiring has everything to do with performance. What you leave yourself open for is questions like “so if I use a wire that is as thin as a human hair, as long as I have the correct voltage going to the motor, I should be just fine?” I think we both know the answer to that.
Let’s say your battery in your car has died. You need to find someone who has jumper cables. you have two people who have jumper cables. One person has a set of cables made from 28 guage ribbon cable like on your printer, and the other person has a set with 2 guage wire. Now they both will allow the correct voltage through, but the AMPERAGE is going to be a MAJOR difference.
SO, now with all of that out of the way, does anyone have anything USEFUL to help with the issue. I will say this, The Velleman motor on the K8200 is rated at 2.5amps, the wiring is rated at 1.4 amps. Does anyone know what the stepper motor DRIVER is rated at?
(brecht) you did amuse me with your post.
If the feed rate (I’m at 100) is too high the motor will stall when the extruder barrel is full.
Try raising Z to 20mm and manuelly turn on extruder heat to 160 or so for pla and when at temp feed the extruder in steps od 10. when motor stalls its full and a stream of pla should be coming out.
Al right, calm down and that’s coming from the grumpy git around here!
[quote]Now the Velleman “tech”. When you say “the wiring does not REALLY influence the torque”, you leave yourself open for some serious scrutiny.
The SI unit for measuring an electric CURRENT is the AMPERE. Wiring has everything to do with performance. What you leave yourself open for is questions like “so if I use a wire that is as thin as a human hair, as long as I have the correct voltage going to the motor, I should be just fine?” I think we both know the answer to that.
Let’s say your battery in your car has died. You need to find someone who has jumper cables. you have two people who have jumper cables. One person has a set of cables made from 28 guage ribbon cable like on your printer, and the other person has a set with 2 guage wire. Now they both will allow the correct voltage through, but the AMPERAGE is going to be a MAJOR difference.[/quote]
If you had looked up the specification of the stepper motors, you would have discovered that they are rated at 1.25 ohm and 3.1v per coil. They are being fed from a 15v supply and clearly are not pulling 12 amps! The stepper driver is limiting the motor current, the value of that limit being set by the trimmer pot. Even with several ohms of resistance in your motor leads, there is still more than enough voltage to exceed the current rating of the stepper motor, let alone achieve rated torque!
I suggest you read this; geckodrive.com/gecko/images … 0Guide.pdf
Look, I really am a nice guy who is usually very calm. I have a very logical brain and can usually figure things out on my own through process of elimination. The frustration comes from posting questions, giving what I have done, and receiving comments and questions asking if I have done the exact same thing I had posted I had already done.
I came on here hoping that someone could either answer my question, which hasn’t been answered yet about the stepper motor driver, or give some ideas as to what might be happening with the stepper motor being weak.
Let’s kind of start over.
My stepper motor for my K8200 extruder seems to be weak(it always has, but seems worse). While printing it will sometimes stop turning like a little rock or something is stuck in the gears, of course that is not the case. The steps I have taken to try and solve this are:
- The gears are clean, nothing stuck in them.
- Make sure the gears are not too close.
- I have heated up the extruder and pulled the filament out, to eliminate the issue of the spring tension and extruder not being hot enough.
- Even though I have no filament in the extruder, I still backed out the tension screw all the way.
- The hobbed bolt nut is not too tight.
This does seem to get worse the longer I print. In the mornings it seems to be much stronger, and weaker as I print more. This is what made me think it could be related to wiring since temperature plays a role in the performance of wiring.
I have since replaced the 28 gauge ribbon wiring with 22 gauge. So far it seems to work much better. I printed something last night that took 3 hours and I don’t think it had a problem once(I didn’t sit there and watch the whole thing). The print seemed MUCH better too. This morning I heated up the extruder and had it extrude some out, and it again seemed much stronger.
Even though changing the wire seemed to help a lot, does anyone know of a stepper motor that is stronger(more torque) that would “plug and play”?
The gauge of the wire does not affect performance since the motors are current controlled, not voltage controlled.
Furthermore, more than 12.000 users are using the same wires, so we are positive that they are not an issue.
Can you measure the setting of the stepper driver when you start printing and when you notice that you get less torque, maybe it drifts?
Did you try to swap stepper driver or motor, to rule out a bad stepper driver or motor?
Wow,
Very strange way to ask for help.
I have one more suggestion and then I will step away.
Did you check the bearings in the extruder?
Maybe one or both are jammed or have trash in them.