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How to measure with Calipers

Posted: 29 Sep 2018, 07:29
by Mats
Hi,

Not really a KisSlicer question and most probably this has been answered before but I can not find anythin about it.

Not really importent for my question but I used:
Printer - Creality CR-10s
Slicer - KisSlicer v2 a 0.4.4 Win 64
Flow compensation 0.9

A'm trying to calibrate flow and got into a small problem, when I messure the thickness with the caliper I get 0.45 with a low pressure on the caliper and 0.35 with a hig pressure on the caliper.

How do I corectly messure the thickness when calibrating flow or is something else wrong when it varies so much depending on pressure?

Mats

Re: How to measure with Calipers

Posted: 29 Sep 2018, 10:00
by smalluseful
Never use high pressure with calipers, just adjust low pressure otherwise you are deforming the material you are measuring.
Also double check that the calipers read zero (0.00 mm) when fully closed. If not clean the blades check again for zero and if
necessary zero out the calipers (button press for digital calipers or move dial for analog).

Re: How to measure with Calipers

Posted: 29 Sep 2018, 11:18
by Mats
Thank you for the answer.

Everything is calibrated including e-step and PLA is measured to be 1.75 so this would indicate that I should use < .9 as flow compensation, not what I thought.

/Mats

Re: How to measure with Calipers

Posted: 29 Sep 2018, 11:51
by pjr
Mats wrote:Thank you for the answer.

Everything is calibrated including e-step and PLA is measured to be 1.75 so this would indicate that I should use < .9 as flow compensation, not what I thought.

/Mats
If your e-steps are correct than flow compensation should be 1. The printer should be extruding the precise amount of filament for your print.

Peter

Re: How to measure with Calipers

Posted: 30 Sep 2018, 04:02
by Mats
I got the feeling last night that a wall of .4mm could be to thin to make flow test on as I feel that each layer may not be exactly on top of the previous one when the wall is so thin so today I printed 3 cubes after calibrating/checking e-steps and setting flow to 1.

Wall thickness -> Caliper -> % Error
0.4 -> 0.50 -> 25%
0.8 -> 0.88 -> 10%
1.2 -> 1.24 -> 3%

From this my conclution is that it is not possible to calibrade flow as an amature on a hobby printer using the .4mm wall methode.

Peter: From now on I will asume that the slicer will work correctly if e-step is calibrated and flow is set to 1.

Mats

Re: How to measure with Calipers

Posted: 30 Sep 2018, 10:34
by frozen.rabbit
That's really not an accurate way to calibrate e-steps.

You want the extruder motor to push 100mm of filament when you tell it to. Trying to come up with a % correction to change your e-steps from test wall thickness is over complicating the process.

Yes, with everything ideal, you would have a flow rate of 1. But there are diameter variations in filament, and different materials have different characteristics.

With the same e-steps on my machine, the current brand of ABS I mostly use, flow rate is 0.95, TPU flex however is 1.15.

It's certainly easier to change the flow in KS rather than digging into your e-steps every time for every material.

I generally print 20x20x10mm closed top cubes for flow. Top layer finish tells a lot. Gaps in top infill, flow is low, nozzle dragging thru top layer and no gaps, flow too high.

Re: How to measure with Calipers

Posted: 30 Sep 2018, 14:52
by Mats
Tank you for the answer frozen.rabbit, I have calibrate e-steps for the printer and it corresponds to the initial setting for my printer. I have never changed e-step just checked it. Had no intention to change e-steps but perhaps use a more scientific way to set flow.

I have seen a lot of videos recomending using hollow cube to calibrate flow and from my tests today I can se that it does not work, specially with thin walls as it seems that the flexibility of thin walls make the wall uneven so it is not possible to measure it with a caliper.

I'm quite new to this but earlier I have done as you say, just looked at the print and corrected the flow, I'm also using ideaMaker and ther I have to use a low flow value to make the print look nice, less than .95.

This was just a test of using a more scientific way to set flow but I will go back to the look and feel way.

Mats

Re: How to measure with Calipers

Posted: 07 Oct 2018, 00:25
by sinned6915
Mats-

This is what I came up with for calibrating and checking E-steps. You should be able to do the same on the CR-10.
https://www.thingiverse.com/thing:2790629
its a remix of Micheal Hackneys caliper way, but much simpler to print.

Yes, calibrate E-steps witht he the flowrate at 1.

I use the same calibrtion cube, but scaled to 1/1/0.16 to make it 4mm tall and print it. I use the scaling funtion with the right click on the model. I also have a squared corner version I will try to link here.

You can print it solid or with infil, it takes the same amount of time. I do solid often. Then you can check the top surface for flowrate and infil overlap and Loop/Solid Infill Overlap with the same print.