After completing the Acro 1515 build and having played around with it for the last few days I have some further questions, although having read the documentation...... I notice that as the Y motors are not linked together its quite easy for the machine to get out of alignment in the Y plane particularly after a crash. I end up measuring the Y distance at each side to realign the gantry. Is this normal behaviour / maintenance with this machine?. I have another home built CNC which has a different type of motor arrangement where 1 motor drives the X and 1 motor drives the Y, and relies of an advanced way of using belts and pulleys to control X and Y with single motors. I feel this seems a bit more stable with this type of design, but may be I need to play around more with this new machine..... The same job that takes for example 1 hr to complete on my existing machine, takes 30% more time on the acro, despite using the same Gcode F setting. I've had a look at the motors and they look similar specs, so wonder if its the belt arrangement making the difference.... thanks.
Grbl v1.1 Configuration CoreXY/H-Bot. But how big? Also a 2*2m? Stock profile does err on the side of conservative so also see Grbl v1.1 Configuration (faster acceleration cuts job times with lots of short moves) and Grbl v1.1 Configuration (max speed on longer moves). Tune at will but take note of reliability, too high will stall. Grbl wiki does describe tuning. Ps: that Grbl wiki still is a must read. Really is.
Thanks Peter, yes, still reading as much as possible, but all still very new when you build yourself. My other CNC (1.2m by 0.8M) came all set from the box and even though I bought the Acro kit, seems there is a lot more to get involved with hence the many questions.... I did speed up things by modifying the Gcode F, but as you say may be less reliability and also accuracy for my application. Will check out the settings though.
That in itself will make a speed difference - Less enertia than the bigger frame likely. F still honors Max Rate. Read the sections linked above.
Yes, set these higher than the F5000 the gcode uses, but will do some further investigations, cant see it being acceleration as my job has small movements... $110=10000.000 ; X-axis maximum rate, mm/min $111=10000.000 ; Y-axis maximum rate, mm/min $112=5000.000 ; Z-axis maximum rate, mm/min $120=500.000 ; X-axis acceleration, mm/sec^2 $121=500.000 ; Y-axis acceleration, mm/sec^2 $122=500.000 ; Z-axis acceleration, mm/sec^2
Spoke too soon, indeed it was acceleration limiting the speed ! Have changed this to 1000mm/sec now and no jumping yet. Not sure yet how hotter motors will get, but is there a typical setting for the acceleration. Appreciate different applications have diff settings, but is 1000mm/sec in anyway extreme for the Acro 1515, thanks
Not too extreme, our stock profiles are conservative to get people going, reliable and safe. But definate scope for plenty of tuning. Motors will not heat up more. Most heat gets generated when motors are standing still. To brake both coils are energised. During moves one coil at a time switches on and off rapidly.
I think increasing to 1000mm/sec may be pushing the limits for my application, definitely more shaking of the X gantry in my case. Dialled it back to 800 as a compromise. Is there any way people beef up the X gantry ? or presume go for one of the other machine which look more substantial...
Heavier gantry, heavier machine = even lower acceleration Low mass = less enertia = better acceleration. Physics is sadly a real thing that limits things to some form of reality at all times. Small and light = faster.
