Gaps between layers, separation ? no adhesion ?

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welo78
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Joined: Wed Aug 01, 2018 8:06 pm

Gaps between layers, separation ? no adhesion ?

Post by welo78 » Sun Aug 26, 2018 8:41 pm

Hello, since building a new 3D printer with RAMPS 1.6 and TMC2130 I cannot wrap my head around an issue that I have whilst printing calibration cubes.

When I try to print a hollow 20 mm cube, watching the cube as it begins to shape circa 5mm from bottom layer, it stops "pushing" or "bonding" the outher shell layers on top of each other but it rather bridges from one corner to the other.

I can visibly see that it does not stick because I think the Z axis steps are maybe incorrectly set? I think it moves too high from previous layer and that is why it starts to bridge.

This is my Marlin steps configuration. The printer is based of off Anet A8. It is a conversion to Anet AM8, with metal frame, better motors, drivers, display. I however kept the original steps.

Any help is appreciated. Underextrusion is not a problem, I have my Extruder steps calibrated correctly.

Code: Select all

#define DEFAULT_AXIS_STEPS_PER_UNIT   { 100, 100, 400, 105 }

#define DEFAULT_MAX_FEEDRATE          { 400, 400, 8, 50 }

#define DEFAULT_MAX_ACCELERATION      { 2000, 2000, 100, 10000 }

#define DEFAULT_ACCELERATION          1000    // X, Y, Z and E acceleration for printing moves
#define DEFAULT_RETRACT_ACCELERATION  2000    // E acceleration for retracts
#define DEFAULT_TRAVEL_ACCELERATION   2000    // X, Y, Z acceleration for travel (non printing) moves

#define DEFAULT_XJERK                  20.0
#define DEFAULT_YJERK                  20.0
#define DEFAULT_ZJERK                  0.3
#define DEFAULT_EJERK                  5.0

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Moorviper
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Joined: Wed May 24, 2017 1:19 pm
Location: Hessen/Rhön - Germany
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Re: Gaps between layers, separation ? no adhesion ?

Post by Moorviper » Sun Aug 26, 2018 9:15 pm

you can calculate it with: https://www.prusaprinters.org/calculator/

when you use tmc2130 now you have to calc it with 256 micro steps
what is the pitch of the anet a8 lead crews?

256 microsteps is not available so choose 1 step and multiply it with 256 if you use it

welo78
Posts: 5
Joined: Wed Aug 01, 2018 8:06 pm

Re: Gaps between layers, separation ? no adhesion ?

Post by welo78 » Mon Aug 27, 2018 7:35 am

Hi Moorviper,
thanks for the reply. Hmm I did not thought of that. I was messing with the settings and altough I do get layer seperataion (no adhesion, gaps) on 400 mm/s when I use 200 the test cube is flawless in X and Y direction (19,98 mm) but in Z it is stretched to IDK maybe 3-4-5 cm ? I stopped the print. It was no longer a cube but a cylinder.

From my understanding I should calculate the Z height like this ? Since it is a direct connection leadscrews to motors I assume the gear ratio is 1:1.

I do not think my calculations are allright though.

Image

welo78
Posts: 5
Joined: Wed Aug 01, 2018 8:06 pm

Re: Gaps between layers, separation ? no adhesion ?

Post by welo78 » Mon Aug 27, 2018 8:34 am

Ok I found some information regarding the TMC2130 stepping.

TMC2130 stepping settings

Seems like you do not actually use the 256 (interpolating) stepping when calculating the steps needed. Since it uses 1/16 stepping interpolated to 256. The correct math should look like this. Can anybody confirm this ?

P.S. It does make sense when I calculate my X and Y stepping being circa 100. Cube does have 20mm in X and Y direction.

Here are the calculator results that I should set for Z axis with TMC2130 set to 1/16 steps.
Image

Here is the calculator results that I should get on X and Y, and which are correct.
Image

Can anybody confirm this information ?

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