why is filament sensor not working correctly?

[frank westerman]

 

  I have tried to make PLA filament (1.75) when I tried to thread the filament on the spool I found that the spool would not start when passing through the lower led and I had to start it with my finger. Then it wouldn't stop until I stopped it with
my finger but it had already stretched the filament super thin and I figured that it was then too thin to interrupt the leds. I contacted Extrusionbot and the said that I should loosen the screws that attache the led frame to the front bar about a 1/4 to 1/2 turn
and this should take care of the issue. I tried that and it didn't fix it and I was wondering if there is a procedure to make sure the beams were working correctly. After I made there suggested adjustment I noticed that the sensor woult activate if the filament
was passing close to the left side but if it was further away then it didn't work . Does anyone have any suggestions?  ( this unit was sent fully assembled )  Thanks 

[frank westerman]

 after some trials of using piece of filament that was made, and I measured it at 1.74mm- 1.76mm in diameter, I used this attached to the pulley wheel and sticking out passed the far end of the sensor block.
i turned on the extruder with only the spool switch on, i then rotated the filament attached to the pulley so the filament would pass through the sensors. i started the spool with my finger in the lower sensor and then
rotated the filament up to the sensor to stop the spool and it worked the filament was in line with the pulley and was about the middle of the gap for the top sensor. i then rotated the filament down to pass through the
lower sensor to start the spool and it didn't work. i made some adjustments to the sensor mount to see if it might be not straight across to each other on the lower sensor and this made no difference. i then bent the filament
to the left till it made the sensor work. This put the filament within a 1/4 in of the left side of the sensor and it would turn on the spool. with this information I contacted customer service and they told me that it might be the controller card
and they are shipping it back to check it out and resolve my problem.

 

[frank westerman]

 I received my extrusionbot back last night. I tested the filament sensor and found that it seems to be working as it should. While they had my unit they called me and said that they wanted to make some upgrades to the unit and that I would only need an extra day to make the changes, so I said great have at it and they were doing the upgrades for free so why not. They didn't tell me what they changed but I did notice when the unit came back that they had put venting holes in the back of the case and mounted a fan to exhaust out the back. I will be trying it out over the weekend to see how it works with the fixed sensor and the venting. They didn't say what what they upgraded they just said is was some minor things.

[frank westerman]

When I tryied to test the unit when I got it back the heater didn't work so I had to return it again and they found that there was a wrong setting in the PID and they reset that and returned it.
I tried it after getting it back again and was able to make some PLA filament and the sensors were working ok, I had some trouble trying to get the hot filament onto the spool to wind it up but after a number of tries
i got it started and was able to make about a 1/4 of a pound of filament on the spool but not without mishap. the pully that is to guide the filament to the sensors and the spool was not rotating and every so often the filament
would stick and if I didn't see it it would fall to the back side of the pulley and then I would have to manually move the spool to get the excess to the spool for it to start working again. I did notice that if I put a metal ruler at an angle across about 2 inches
below the extruder that the filament was being forced out to where the pulley front edge is and it seemed to help. (Is the pulley supposed to rotate freely or not?) I also noticed that the filament on the spool goes to the middle and when it falls to the side it is really loose
and doesn't stack well after that. Has any one devised a way to have the filament spool like a fishing reel does? but all in all the machine seems to create the filament well and It just takes some practice to get it started on to the spool.