if you sent me a pm i am not seeing it, you can email me at ashwood1296@gmail.com if you like
i dont want to say who told me to run at ultra high speeds, but it came from two who should be in the know. i still think that i have an abused x stepper motor and bought my first dial indicator this week. i did not say that i knew how to use it but i should know the results today. i have been using the offset machine strategy. in this cut everything outside the rope was done in using raster cutting up and down the x at a much more reasonable speed. inside the rope offset. to me it looks much better but i still think a new x stepper motor is in the future for me.
unless i am doing something wrong my brand new dial indicator is telling me that i have .013 of movement on the x which seems like more than just a tick, i am also putting a lot of pressure on the x while trying to take the reading.
Cowboy,
How much sanding has been done on the last few images you've posted?
Reason I ask is because what you're pointing out as a "problem" with your carvings is what I've grown to expect as completely normal and unavoidable, based on my forays into 3D work. No amount of tuning/tightening, pinion replacement seems to make a difference with my machine.
Always have some lines visible, just like you're showing here, and a detail-destroying amount of sanding to clean up any 3D work coming off my machine. Criss-cross finishing path is hard to watch, as it just seems to rake another row crop effect atop the original one, saving neither time nor elbow grease.
Oh yes, I've wrecked several carvings with my excessive fussing with sandpaper, so I've all but abandoned the pursuit, unless it's required of me.
Still, with examples like yours, Scott P, and countless other guru's here, you guys sure make it look totally normal to turn out pristine carvings straight off the machine... Could it really be possible, given more practice and tweaking?
Sometimes wonder if the desktops are simply more agile based on their smaller size, as I watch my 9660 gantry bounce and vibrate the heck out of the table, as that heavy spindle and Z car diligently tries to replicate all the nooks and crannies of a detailed carving. (Like watching an elephant try to figure skate.)
You guys are in a class all your own as far as I'm concerned.
(I'd love to join you, so any links to videos, suggested reading, or threads here would be appreciated.)
Jealous,
jeff
it may be me being too anal and i am guilty of being that. a l. here is one of my latest at blistering speed using an offset tool path. the lines are more visible in it. a lot of times in 3-d you just cant reach the area that needs to be sanded. i use a sanding mop for that and it helps but even it has its limitations.
Rick,
It may be helpful to cut the same file in a product like HDU.....
Material ( wood ) is known to move while it's being cut....
HDU shouldn't.
Then compair the finished items.
Michael
i dont even know how to spell hdu but thanks for the idea. when i went from offset to raster and slowed my speed down it seemed to help a lot. i have taken 2-3 readings with the dial indicator and each time it shows too much play in the x stepper motor. i have abused it perhaps one to many times over the years. all i do is large 3d plaques.
Jeff and Rick,
Raster always, but do so with the axis that runs the length of the gantry and not the length of the table/moving table. With improper ramp settings and the full weight of the gantry or table rastering back and forth, you can set up a resonance/jiggle, that is transferred to the cut, when that axis has to ramp or slow down to allow the Z axis to raise up and over any features and also when it takes off again. If default ramp settings are being used, this situation gets amplified. Also, try to match feed and plunge rates to aid in this ramping situation. If you have excessive backlash, then that will also add to it. 0.013 is excessive Rick, but I'm not to suprised if that motor is the one that you raster with and if it is also the table one. Make sure that the pinion is tight and also that it's tight into the rack (I know you've been through this but...). When checking with the dial indicator, don't apply any more force than needed to take up the slack, because if you apply more, you can start to turn the pinion/motor slightly before it will totally loose steps (yours being a standard machine).
A question for Rick, when you do a offset toolpath and it starts at the center of the design, when it gets to the final outermost pass (like the last perimeter or so), does the tool start to do a lot of up and down Z moves when it should just make a smooth steady one depth perimeter pass? Whenever I have used that toolpath strategy, the final pass or two will take forever because it has been told to basically do a Z-hop all the way around. This is an Aspire/rim pixel thing and one reason I never use offset. With the amount of backlash you have, as you circle around the design, that backlash will come and go as it changes direction and cutting force and in turn translate those ripples to you finished product.
I've posted it before, but read and reread and test and test to find values that work for your machine and task.... Tune your tool. I know it's a daunting task, but it you don't take the time, you don't reap the rewards. This was done rastering Y across the gantry (across the grain as well) with a 2mm ballnose 8% stepover @14 hours and minimal cleanup.
Here's a video of the kind of motion one should strive for with 3D raster toolpaths. Granted, this machine is no longer under SB3 control and SB3 will never get this smooth, but you can get close if you take the time to tune it (and raster across the gantry). https://youtu.be/dJdIBX7k8EE
Scott