Wanting to go back to servo setup

I do not like the amount of play in the current servoless setup on the smartrap. I feel that the servo setup will allow for the hotend to have way less play. I also have odd endstops and I want to be able to use them. Does anyone have a file for a servo setup with GT2 belt and for the jhead lite v2.1? Or any suggestions that would help my process?

I felt the same way. I could not get an even first layer because I believe the resistance from the bowden tube and wire bundle is inconsistent across the build plate and affects the switch activation. The Marlin autolevel compensation could not deal with the variances, even with the delta parameter that was introduced.

I went ahead and redesigned a mount for the 6mm bar version that integrates a cheap inductive sensor and Reg's MK2 hotend. The sensor drives a simple 12v relay circuit for the RAMPS z end switch input. I glued aluminum foil to the underside of the glass plate and located the sensor to trip within 2mm of the top of glass.

So far, it seems to be working rather well.



Edited 1 time(s). Last edit at 01/07/2015 08:48PM by botbuilder.

To fix the problem I added a compression spring to make sure the head is allways pushed down. The spring should not opose to much force otherwise entire X axis will bend.

botbuilder > do you get consistent measurements from that sensor?

The spring approach helped, but I still got uneven first layers. I also didn't like the wobble that was introduced with a single hinge point. Snugging up the screw eliminated the wobble, but increased the resistance in the arm that holds the hotend. Seems like I was always fiddling with the screw, spring tension and switch lever.

I haven't tested the sensor repeatability itself, but I can say that running the autoleveling with the sensor produces a perfect first layer without fiddling with anything.

So I will go with the inductive sensor. Is it in config h? And do I put it so that it is above the tip of the hotend? I'm confused as how to set it up.

My apologies. I lost the password to my account knife-edge a month or so ago and I am still logged on on my phone. I sent the message above on my phone. Both are me. I will delete that account when I can find out how. But the questions still remains.

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griffinaeronautics
I do not like the amount of play in the current servoless setup on the smartrap. I feel that the servo setup will allow for the hotend to have way less play. I also have odd endstops and I want to be able to use them. Does anyone have a file for a servo setup with GT2 belt and for the jhead lite v2.1? Or any suggestions that would help my process?

I have gone back to servos as well, less problems.
What I have done different and it works really good is to use long button tactile switches instead of the micro switch.
This is much better for a Z probe, more streamlined and also doesn't have the problem of the arm bending after several uses and then having to re-set it again.
It is also more sensitive and needs very little pressure. The tactile switch needs the logic reversing in the firmware, same as an opto switch.
I am using really small servos too, ultra micro size.







Notice I am also using solid Delrin bushes instead of linear bearings.
These work far better and are quieter too. Been testing them on a single machine and so far done over 3000 hours of printing with excellent results.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

I don't use autoleveling. It seems it creates more problem than it solves. I can tune bed leveling manually and I just do a single point probe to do the Z height check. No problem since then and I didn't have to worry about recalibrating in months. I plan to use a Hall sensor probe instead of microswitch for better accuracy. I need some time to design it. There is another good aspect of hinged print head. In cases when you have plastic resedue on print and head bumb into it it can move up and avoid crashing. I saw this couple of times and I like it.

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ldanut
I don't use autoleveling. It seems it creates more problem than it solves. I can tune bed leveling manually and I just do a single point probe to do the Z height check. No problem since then and I didn't have to worry about recalibrating in months. I plan to use a Hall sensor probe instead of microswitch for better accuracy. I need some time to design it. There is another good aspect of hinged print head. In cases when you have plastic resedue on print and head bumb into it it can move up and avoid crashing. I saw this couple of times and I like it.

Before auto bed levelling I used a hall effect sensor, they are extremly accurate.
I made a simple micrometer adjustment for moving a small magnet up and down to set the height position. This was mounted as part of the non moving part of the machine.
The hall effect sensor was fitted with a LED and a small resistor inside a very small printed housing. This part went up and down with the Z axis.
When the Z axis moved down and came close to the magnet, the LED would come on to show that it had activated.
To adjust, the knob that was on the end of an M3 screw that had the magnet on the end was adjusted to get the sweet spot. Once set I used a lock nut to stop the adjustment going out. Never had to change it once set.

Here are some photos and drawings that may help you.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

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knife-edge
So I will go with the inductive sensor. Is it in config h? And do I put it so that it is above the tip of the hotend? I'm confused as how to set it up.

If you were already using autoleveling with the switch, the changes to the config.h are trivial. The tip of the sensor is only 1-2 mm above hotend.

Here is a good video that explains how to set it all up:

https://www.youtube.com/watch?v=EcGFLwj0pnA