Problems

Aze
Messages : 1928
Enregistré le : 11 mars 2017 14:13

Re: Problems

Message par Aze »

It's normal if your settings are different between X and Y.

Actually, the M8 leadscrew in X is a small mistake on this machine. You can't accelerate and go fast enough with that. The X axis limits the whole machine.
That's why I quickly made this upgrade (using ACME leadscrew with 8mm lead -> you can put same acceleration and feedrate than Y):
https://www.thingiverse.com/thing:2417296
(don't look at my Marlin's settings in thingiverse: I use ACME leascrew 8mm in X, ACME lead 2mm and 32 microsteps in Z. So my R-CNC goes minimum 10 times faster than yours, with better accelerations: https://www.youtube.com/watch?v=nNKhC2bFKA8 )

Romain is actually drawing an upgrade to put the same system (GT2 belt with 60teeth pulley etc) than Y. He's working on it at this moment!
It's the best choice to use GT2 belt 10mm on both axis, because as you can see, we need the same speed & acceleration on both axis.

If you want that Y go slower, just change your settings in Marlin (same values than X). And it's better to do that, because otherwise your spindle won't be happy to cut fast in one direction and slowly in the other.
Copy/Paste your Marlin settings here if you're not sure of what you're doing.

Take a look at the other remixes of the machine (the Z nut is cheap and you can gain some speed, the external waste board adjustement is usefull):
https://www.thingiverse.com/thing:2159840/#remixes
Grzegorz
Messages : 33
Enregistré le : 23 mai 2017 20:56
Localisation : Poland

Re: Problems

Message par Grzegorz »

I'm completely not sure what I'm doing :oops:
I hope this is a good part of Marlin:

// MOVEMENT SETTINGS
// @section motion
//

// default settings

#define DEFAULT_AXIS_STEPS_PER_UNIT {2560,240,2560,200} // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE {10, 180, 6, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {25,50,20,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION 25 // X, Y, Z and E acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // E acceleration in mm/s^2 for retracts
#define DEFAULT_TRAVEL_ACCELERATION 25 // X, Y, Z acceleration in mm/s^2 for travel (non printing) moves

// The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
#define DEFAULT_XYJERK 2.5 // (mm/sec)
#define DEFAULT_ZJERK 0.4 // (mm/sec)
#define DEFAULT_EJERK 5.0 // (mm/sec)
Aze
Messages : 1928
Enregistré le : 11 mars 2017 14:13

Re: Problems

Message par Aze »

It's the good part of Marlin.

You're not alone to have some 'reset' problems and it looks like the Arduino is saturating. If it's working for you with these settings (=slower for the arduino actually) you can try something else:
take away some microsteps on X and on Z. Actually, you're using M8 leadscrew on both axis with 16 microsteps on a 200 steps nema (17 or 23) -> to make 1 round of the motor, you need to make 16*200 microsteps=1200 impulses. With a M8 screw, 1 round=1.25mm, so 1 impulse = 1.25/1200 = 0.00104.. mm !!! It's way too impressive for what you need and you're Arduino is not fast enough to give so many informations.

Even without jumpers at all (=without microstepping), you still have 1.25mm/200=0.00625mm of precision. It already good enough! And less microsteps=more power on your motor and your arduino not running (and heating) as hell!

So, now you start to understand a bit how it works and you have to try different settings. For me, it's better for you to have less microsteps (or none) and a bit more speed on your X axis. If you're using a TB6600 with nema 23 on your X axis: try to put no microsteps (or less) on your driver, then come back in Marlin and changes the values.

Some explanations in Marlin:

here you change the steps (or microsteps in fact) for X, Y, Z and E (forget this last one, it's E=Extruder for 3D printers). Actually for 1mm, you need 2560 microsteps (=200*16/1.25). If you choose 8 microsteps, put 200*8/1.25= 1280, etc...I you want, use this calculator:
http://www.prusaprinters.org/calculator/ (go to "Steps per millimeter - leadscrew driven systems" paragraph).
For Z, actually it's the same problem, you really don't need so much microsteps, so you can change it too. It's just a bit harder to change the settings for the driver (A4988 for you I suppose), you need to put away some jumpers. But just look at these pictures and you'll understand:
http://docs.my-home-fab.de/images/my-ho ... epping.jpg
http://cdn.shopify.com/s/files/1/0627/7 ... 7770439408
#define DEFAULT_AXIS_STEPS_PER_UNIT {2560,240,2560,200} // default steps per unit for Ultimaker

here it's the maximum speed (again, it's X, Y, Z and E). Easy to understand. Try to put 15mm/s for X after changing your microsteps. Faster is better for a CNC. Go to ebay and start buying 60 teeth and 20 teeth pulleys, 2m of 10mm GT2 belt, 2x625z , 2x608zz , etc (same as Y axis), because Romain will make the same system as Y axis soon.
#define DEFAULT_MAX_FEEDRATE {10, 180, 6, 25} // (mm/sec)

The accelerations: how it's accelerate before going to the max_feedrate. Come back to 50 in X after your changements. These values are used when milling and when traveling without milling.
#define DEFAULT_MAX_ACCELERATION {25,50,20,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.

It's the acceleration for all axis when 'printing' (for us, when 'milling'). Come back to 50 if you can after changes.
#define DEFAULT_ACCELERATION 25 // X, Y, Z and E acceleration in mm/s^2 for printing moves

just for 3D printing:
#define DEFAULT_RETRACT_ACCELERATION 3000 // E acceleration in mm/s^2 for retracts

Easy to understand. Try to come back to 50.
#define DEFAULT_TRAVEL_ACCELERATION 25 // X, Y, Z acceleration in mm/s^2 for travel (non printing) moves

This one means than you start directly at 2.5mm/s and not at 0mm/s before using the acceleration setting (useful for 3D printing, otherwise you have to much plastic droping at place each time you're changing direction). For CNC, it prevents to 'burn the wood or melt the plastic' at each corner you're doing. Come back to 5 if you want.
// The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
#define DEFAULT_XYJERK 2.5 // (mm/sec)
#define DEFAULT_ZJERK 0.4 // (mm/sec)
#define DEFAULT_EJERK 5.0 // (mm/sec)
Grzegorz
Messages : 33
Enregistré le : 23 mai 2017 20:56
Localisation : Poland

Re: Problems

Message par Grzegorz »

It looks like everything is fine now
I had done all you said. Microsteps on X and Z down to 8 and all settings in Marlin back like it was before.....so far I'm happy.
Now I have to connect everything like it suppose to be and do some milling.
Thank you very much your explanation was excellent (perfect "idiots guide")

Thanks again Aze
Aze
Messages : 1928
Enregistré le : 11 mars 2017 14:13

Re: Problems

Message par Aze »

You're welcome. Time to make some chips now ;)
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