## 2021 02 03 

NEXT REV: you've mounted the hotend static, and the motor floating post-loadcell. However, loadcell deflection is really minimal, and you could fix the motor / mount the hotend on loadcells. This would let you touch-probe the bed w/ the nozzle itself, for zero calibration etc. 

## 2021 02 27

I have this together and, though some network struggles still exist, am able to capture data from the hotend. 

This was calibrated with 50g -> 1kg, in 50g increments, but I think there is some hysteresis as there is a PTFE tube in the filament load path... 

I've gathered [two](2021-02-26_extruderTestData_1.json) [datasets](2021-02-26_extruderTestData_2.json), running filament at 100, 200, 300, and 400 mm / min. The datasets are time-series and include extruder feedrate (in mm/sec), loadcell readings (in netwons) and temperature readings. The time steps / readings should be synced to about ~ 2ms. 

![res](2021-02-26_extruder-test.mp4)
![img](2021-02-26_extruderTestData_2.png)

## 2021 01 24

This part works, new toolchanger feels good also. 

![he](2021-01-24_hotend.mp4)

![squeeze](2021-01-24_hotend-squeeze.mp4)

![print](2021-01-24_hotend-print.mp4)

## 2020 12 27

Revisioning this to bring it up to speed with toolchanger deltas, also found a new loadcell to suit the smaller toolchanger design, that's UXCell PN `a15110200ux0247`. 

So I've to revision to tighten this up, but it should be pretty straightforward. I think I do this, then fab it all, and can bring loadcell probes in to the mix once I have two of these swapping pretty well... would love to have i.e. an 0.8mm infill tool and 0.4mm perimeter tool. 

- adjustment for smaller loadcell, 
- adjustment to hotend pinching clamshell
- rm interference between hotend / bowden top and loadcell 
- more-better planar constraint on hotend / coolside / front-of-hotend clamshell 

Great, this is done, so I'll fab and then bring heaters & loadcells online. 

![gg](2020-12-27_glue-gun.png)

## 2020 12 10 

Assembled one of these, have some hardware bugs but will continue to bring this online instead of revisioning:

- could use a third thru-bolt to get the planar constraint w/ the second half of the hotend-pinching clamshell 
- loadcell to bowden connector does not clear (visible in CAD: move out or move up) 
- m4 head-thru on top of loadcell on hotend not wide enough 
- more pusher-part (extruder / top half) clearance to plate, notice misalignment / out of squareness at loadcell mount 


## 2020 12 06

Did a bunch of development for this thing offline. 

![gg](2020-12-06_gluegun.png)

It's E3D hotend compatible, I'm using a Dragon hotend. Has a loadcell inline to measure extrusion force, hotend fan but no part cooling fan yet, etc.