January 26, 2019 at 6:09 pm #85833
One of these would have been awesome when I was in theater in high school. I did 3 years in set production and had a blast. The last two years I got the art teacher to let me work on the sets, then she’d grade me on them as art projects. Our end of year big productions were Sleeping Beauty, Music Man, and Midsummer’s Night Dream.January 26, 2019 at 8:00 pm #85872
Sorry I was gone all day.
I am glad it worked out. Speeds are hard to set on the Lowrider. For most people they are using a 1″ bit in 1/2″ material, but the taller you go…. it gets more complicated. For your cut if you want to do more foam with such a tall bit I would say decrease all accelerations and go hog wild on speed. Might as well do all the pieces in one go, or at least most of them. That will take advantage of the faster speeds an negate the lower accels. But remember, while one is cutting you can be working on the previous one. A robot is doing the work so it isn’t like you are wasting time, (unless you just sit a stare at it like I do).
I have been thinking about this all day though. Firmware changes and such.January 26, 2019 at 10:38 pm #85891
Barry – yeah my kid is a senior this year, and has done 4 years of theater. They are doing much ado about nothing, and these will be the railing posts on the second story balcony. When the main construction guy showed me the picture of the set they were replicating, I got the light bulb above the head to make these.
Ryan – no worries, we got it sorted. One other observation I will share is that with the really long bit, it had considerable tip wobble in the middle speed settings. Speed 1&2 were fine, 3&4 were pretty bad wobble, and 5&6 were back to smooth, but it caused the tip to heat too much. So I am thinking the middle speed must have had some sort of harmonic causing the vibration. It’s that or something is wrong with my router. So I tried to raise the router in the housing so the gantry wouldn’t be so high, but I am thinking that may have made it worse. I think I will lower the router and raise the gantry some to see if the vibration improves any.
As fas as the firmware changes, maybe consider a low rider branch? I think pretty much any low rider will be subject to the slower Z speed just due to the design and weight of the gantry. I instantly saw the difference between 30 and 8 for the max in FW. It just sounded right. Thanks again for all your patience and help.January 26, 2019 at 10:48 pm #85892
So the default accel is 400, move to 300, or?January 27, 2019 at 7:37 am #85921
I instantly saw the difference between 30 and 8 for the max in FW.
Acceleration and max speed are a matched set. If acceleration was 600mm/s/s and the max speed was 5mm/s it wouldn’t work. It is a balance. It also depends on your build. As it is most have no issues with it as is and have not for a very long time. A few issues have popped up recently so I will tweak the settings a little bit as it is easier to control that than fine tune a Z axis. I suspect your Z is a bit tighter than most. It is not an easy choice, or not as easy as it used to be. 8, is too slow, as there were tons of complaints, but maybe 10-15 with a slower acceleration. Too slow of an acceleration effects every single move, and on a 3D carve they are rarely long enough to make it out of that curve.
I suspect this might be popping up now as we are using S curve accel and not jerk. With Jerk I had it sorted, but now it needs a revisit.
So the default accel is 400, move to 300, or?
Try out a few, pay attention to 90 degree corners, too low and you will get charring, too high and you could skip a step. Acceleration has a huge impact on job time though (at least for the size jobs I typically do).January 27, 2019 at 9:36 am #85944
My issue was the typical only skipping Z steps on one side when going up too fast. For this particular job, 8 is fine for me. Really the acceleration is at the end of each row, as this job doesn’t change z along each pass, but right after the Y movement to the next row, so slow is ok for me on this one. But I know you are looking for settings that work in general. I will try 300 and see if it acts more smoothly, and post my findings. As far as the Z axis tightness goes, I loosened up most of the connections, but when I do an emer stop it drops cleanly down on the far side, but typically hangs about an inch up on the close side (also the side the skipped steps) so I will see about double checking tightness on all the normal things with the lead screw and z bars. For your data collection: my table is 24” in X and 96 in Y, so a smaller build.
1 user thanked author for this post.February 5, 2019 at 7:21 pm #87622
For anyone reading this far into the thread, I completed 24 of these, so I feel like the settings are valid. I want to restate, these settings were selected for cutting HD foam as the final medium, not just for testing.
First I changed the max default feed rate for the Z axis to 12 from 30, and the default acceleration to 300 from 400 in the firmware. This prevented the Z axis from moving too quickly and skipping steps. The default acceleration seemed to keep it from being jerky with the high feed rates.
I used a 1/4 inch ball nose end mill, 6 inch total length (It was good being able to get the vac nozzle under the gantry to remove the chips). I found that the lowest speed setting on the dewalt 611 was the best for foam. I made a Z DOC at 39mm so it could clear the most material in a single cut. I set the rough clearing at F2500, and the finish pass at F3000. Once I saw that those speeds were ok during milling, I used the fedd rate slider in repetier to push the roughing to 125%, and once the rough cut was done, I pushed it up to 150%, and even 175% at one point. I know this is much faster than most people like to move the machine, but in foam it was great. The only issue I had was the vacuum can filling up with so much foam debris. (small shop vac) It was smooth movement and a clean finish.February 6, 2019 at 4:39 am #87660
Any pictures of your mountain of foam parts?
1 user thanked author for this post.February 6, 2019 at 12:52 pm #87770
I didn’t grab any of the pile, but I did take some cool vids if anyone is wanting to see the cutting in action. Pretty sure the files will be too big to upload directly, so I can post to YouTube or something else if anyone has a better option. I will also throw up some photos when the set is complete showing how I used them.February 11, 2019 at 5:05 pm #88769February 11, 2019 at 6:31 pm #88775February 11, 2019 at 6:46 pm #88779
That looks great. Good job on the miters too. Thanks for sharing.February 12, 2019 at 10:45 am #88849
Those came out amazing! That gives me some ideas for sure.February 12, 2019 at 1:03 pm #88880
Jeffeb3 I made a hot wire like you suggested. It worked amazingly well for the miters. Once I had the correct temp dialed in, they went through very nice and smooth. Once they go up onto the set and get painted, I will post another pic.February 12, 2019 at 1:46 pm #88895
We had a heated wire in the shop class I took in middle school It cut through foam really well, and it left a good finish. Glad it worked for you.February 18, 2019 at 1:34 pm #89701February 18, 2019 at 2:09 pm #89710
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