What do you mean 100% feedrate? What is your velocity in motor tuning, and what is the feedrate in the g-code?
Assuming you're doing 3D work, what is the stepover?
You need to give us a lot more info.
Im using a homemade Cnc machine with Mach 3, im using a 1/4" router bit and am cutting on a project that's almost like a 20oz pop bottle cut in half. Im cutting at 100% feed rate and its almost been 3 hours and its maybe 1/4 of the way finished. Any way of speeding up the process without it effecting the project in a bad way?
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What do you mean 100% feedrate? What is your velocity in motor tuning, and what is the feedrate in the g-code?
Assuming you're doing 3D work, what is the stepover?
You need to give us a lot more info.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
as stated you will need to provide more info:
Spindle speed
feed rate
depth of cut
radial depth(step over)
If you can use a larger diameter to do the roughing then finish with the 1/4".
Sight unseen, you should use the deepest pass depth and largest stepover you can for the roughing cuts. Of course this might leave too much waste if you're using a smaller bit for the finish pass. Also if possible use a straight endmill or bull endmill for the roughing pass, it will remove about 40% more material than a ball endmill...
I have being trying to speed up my machine too. My setup consists in the following:
1. Machine Type: Moving Table Homemade CNC (MDF)
2. Driver board: 3 axis HobbyCNC EZ driver board.
3. Motors: Stepper Motor Model # 57BYGH303, rated at 208 oz in
4. Software: Mach3
5. Lead screw: 5/16 18 Thread
6. Driving nut: 2x wood brass inserts oposite to each other and adjusted to minimize backlash
7. Motor Tuning Velocity: @ full step (3600 Steps/in) 75 ipm
8. Motor Tuning Velocity: @ 1/2 step (7200 Steps/in) 50 ipm
9. Motor Tuning Velocity: @ 1/4 step ( 14400 Steps/in) 45 ipm
10. Sheerline 1/2 pulse enabled.
11. Kernel speed: 6000 Hz
12. CV option enabled.
I would like to run my machine at full step with 75 ipm velocity but this seems to cause too much jerking on the motors. The machines runs smooth at 1/2 and 1/4 steps but Im not too happy with these speeds. I machine mdf at 35 ipm with .1 depth cuts with a 1/4 in router bit. Im going to experiment with shallower cuts at higher speeds to see if I can speed up the process.
I was wondering if there is a way to set the machine at full step without the jerkiness, for lack of a better word, or if I need to change my hardware ( i.e. motors, board or lead screw). Any advise? Thanks in advance!
First, let me say I am not an expert. But I do have some ideas how you can speed up your machine.
- raise the dv voltage (so long as it is allowable for your control board. ) I believe the hobbycnc board is rated to 36 vdc. You can upgrade your board to a gecko 540 which I believe is rated to 50 vdc.
- introduce a gear ratio - optimize it for you torque/power curve. This should take into account your desired cutting/jog speed. I've done this for servos, not a stepper system, so maybe someone can chime in. You can change the gear ratio with belt/pulleys, or by increasing the pitch of your screw.
- obviously you understand the mechanics of microstepping.
Those are some ideas, hopefully that gives you one to move on.
Would the stars shine if nobody were there to observe them?
I'd start by upgrading those screws; changing from 18 TPI to something 10 or 5 TPI should speed your machine up dramatically. At 18 TPI you advance way too little with each revolution, and it's worst considering that steppers' torque curve drops at high speeds.
I second Walky's advice -- for steppers, you really don't need or want too much mechanical advantage in most cases. Most folks running screws on DIY machines gravitate towards multi-start screws like 5 start ACME -- this has an effective ratio of 2 turns per inch, and is significantly faster than even standard 10 turn per inch ACME, sometime 2-3X. Definitely upgrade the screws first -- the higher pitch and higher efficiency will both work to your advantage.
Best regards,
Ahren
CNCRouterParts
dang at 18 tpi that machine is painfully slow, like mentioned before, change over to a multi step acme screw and dumpster cnc nuts , like a 2 rotation per inch and that will make your machine capable of going 8x faster. it will stress your steppers more, and at 208oz im not sure if i would change it that drastically, if you had 465oz steppers i would go 2 turns per inch, with yours maybe 4 turns per inchu