topic 4th Axis Wrapped Toolpath Feedrates Too Slow in Fusion Manufacture Forum

4th Axis Wrapped Toolpath Feedrates Too Slow

Anonymous — Mon, 06 Jan 2020 22:56:10 GMT

I'm having trouble post processing accurate feeds in a wrapped 4th axis tool path. I have successfully posted the tool path and cut a part, but feed rates are too slow (guessing 10%-25% of what it should be) when simultaneously moving the rotary axis and linear axis. I am currently using deg/min. I have tried g93 inverse with similar results. I am using the most up to date post processer I can download from Fusion for my machine "Okuma Mill with rotary table". My machine is running an Okuma OSP p200m control.

Please tell me if you have any suggestions. I've tried everything I can think of.

Thanks, George

My tool path looks like:

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

daniel_lyall — Mon, 06 Jan 2020 22:58:44 GMT

Can you post a model that has this problem, To attach a file Go to File -> Export and save as a .F3D Archive File and attach it to your next post, if you can not post the file you can PM it to me or say in your next post you can not post the file and one of the Guys that do NDA work will help.

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

Anonymous — Mon, 06 Jan 2020 23:07:42 GMT

My cutting rate for this tool is 40 ipm.

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

Anonymous — Mon, 06 Jan 2020 23:41:40 GMT

Update: I am able to post a program with feed rates that appear to be my desired feed rates using a post called "HAAS - A-axis (pre-NGC)" although there is a different Haas 4th axis post specifically for inverse time feed, they both post in G93 inverse.

I would much prefer to get the Okuma post to work properly, it would same me the time and potential errors of manual editing.

How could I get the Okuma post to feed the rotary axis like the Haas post?

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

Anonymous — Tue, 07 Jan 2020 18:18:11 GMT

Here's another example, I tried to make it as simple as possible. This is a wrapped contour on a 2" diameter cylinder. I am asking for a feed rate of 40"/min.

Please correct my math if I am incorrect..

40"/min converted to deg/min on a 1" radius (2" diameter) is as follows:

circumference= 3.1416*2.0=6.2832

6.2832/360 degrees=.01745

every degree = .01745"

40ipm/.01745=2292.26 deg/min

My posted program is showing a feed rate of 228.969 roughly 1/10th of desired feed rate

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

bob.schultz — Tue, 07 Jan 2020 21:24:24 GMT

Hello George,

You will need to make a couple of changes to the post to get your desired output. First there is an issue with the Okuma post when direction codes for the rotary axes are not output. Please add the following code to the getRotaryDirectionCode function to properly set the previous ABC angles (we will updated this in the stock post processor).

function getRotaryDirectionCode(abc) {
  if (properties.useTableDirectionCodes) {
    var delta = abc.getCoordinate(masterAxis) - previousABC.getCoordinate(masterAxis);
    previousABC.setCoordinate(masterAxis, abc.getCoordinate(masterAxis));
    if (((delta < 0) && (delta > -Math.PI)) || (delta > Math.PI)) {
      return cAxisDirectionModal.format(16);
    } else if (abcFormat.getResultingValue(delta) != 0) {
      return cAxisDirectionModal.format(15);
    }
  } else {
    previousABC.setCoordinate(masterAxis, abc.getCoordinate(masterAxis));
  }
  return "";
}

The next change in the getFeedDPM function modifies the DPM feed rates from a combination of FPM and DPM to straight DPM. All controls are a bit different in the way DPM feed rates are calculated when there is linear axes movement involved. This change will not be placed in the library post, so you will need to use your modified post.

if (tcp) { // TCP mode is supported, output feed as FPM
    dpmFeed = _feed;
  } else if (true) { // standard DPM
    dpmFeed = Math.min(toDeg(_moveLength.abcLength) / moveTime, maxDPM);
    if (Math.abs(dpmFeed - previousDPMFeed) < dpmFeedToler) {
      dpmFeed = previousDPMFeed;
    }
  } else if (false) { // combination FPM/DPM

If you find that the feed rates are still off when moving both the linear and rotary axes in a single block, you can change it back to combination FPM/DPM and change the pulse weight to 1 for the rotary axes.

var dpmBPW = unit == MM ? 1.0 : 1.0; // ratio of rotary accuracy to linear accuracy for DPM calculations

This will also get you the feed rate values you are looking for when only the rotary axes move, but will take into account the linear axes when both move.

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

will_1 — Tue, 07 Jan 2020 21:37:52 GMT

Hi @Anonymous ,

I think there is an error with the inch calculation in the post-processor you are using. To test you could change the output units to mm and see if those feed rates are correct.

If you would like to change the post yourself to test if this is the issue, change this line...

var dpmBPW = unit == MM ? 1.0 : 0.1; // ratio of rotary accuracy to linear accuracy for DPM calculations

to...

var dpmBPW = unit == MM ? 1.0 : 1.0; // ratio of rotary accuracy to linear accuracy for DPM calculations

Please let me know if this does fix your issue so we can update the post processor on our end.

Thanks,

Will Watkins

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

Anonymous — Tue, 07 Jan 2020 23:49:03 GMT

I made the two edits to the "Okuma Mill with rotary table" post, and it looks to be working properly.

I'll do another test part with more combined rotary/linear tool paths

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

Anonymous — Wed, 08 Jan 2020 00:00:30 GMT

I modified the test part for a full circular contour wrapped on the cylinder to see if the deg/min feed rate varies properly.

It appears to be correct. I'll have to run in the machine to know for sure, but it looks right.

See posted program below:

O1001
(T1 D=0.25 CR=0. - flat end mill)
N1 G40 G80 G90 G94 G17
N2 G20
N3 G00 Z400.

(2D Contour2)
N4 T1 M06
N5 S5000 M03
N6 G15 H01
N7 G00 B-91.448
N8 M08
N10 G00 X0. Y0.1221
N11 G56 Z1.6 H01
N12 B-91.448
N13 Z1.2
N14 G01 Z1.0394 F40
N15 Z1.
N16 Y0.1232 B-91.155 F1898.811
N17 Y0.1245 B-90.562 F2038.921
N18 Y0.1249 B-90. F2199.77
N19 Y0.1245 B-89.438
N20 Y0.1232 B-88.845 F2038.921
N21 Y0.121 B-88.244 F1898.811
N22 Y0.118 B-87.658 F1771.322
N23 Y0.1142 B-87.098 F1650.931
N24 Y0.1096 B-86.552 F1537.781
N25 Y0.104 B-86.016 F1435.427
N26 Y0.0977 B-85.51 F1340.099
N27 Y0.091 B-85.053 F1247.875
N28 Y0.0841 B-84.648 F1154.939
N29 Y0.0762 B-84.26 F1061.911
N30 Y0.0676 B-83.896 F969.335
N31 Y0.0584 B-83.573 F873.415
N32 Y0.0491 B-83.304 F770.169
N33 Y0.0396 B-83.086 F655.659
N34 Y0.0297 B-82.913 F533.332
N35 Y0.0195 B-82.788 F403.546
N36 Y0.0095 B-82.715 F260.375
N37 Y0. B-82.691 F95.08
N38 Y-0.0095 B-82.715
N39 Y-0.0195 B-82.788 F260.375
N40 Y-0.0297 B-82.913 F403.546
N41 Y-0.0396 B-83.086 F533.332
N42 Y-0.0491 B-83.304 F655.659
N43 Y-0.0584 B-83.573 F770.169
N44 Y-0.0676 B-83.896 F873.415
N45 Y-0.0762 B-84.26 F969.335
N46 Y-0.0841 B-84.648 F1061.911
N47 Y-0.091 B-85.053 F1154.939
N48 Y-0.0977 B-85.51 F1247.875
N49 Y-0.104 B-86.016 F1340.099
N50 Y-0.1096 B-86.552 F1435.427
N51 Y-0.1142 B-87.098 F1537.781
N52 Y-0.118 B-87.658 F1650.931
N53 Y-0.121 B-88.244 F1771.322
N54 Y-0.1232 B-88.845 F1898.811
N55 Y-0.1245 B-89.438 F2038.921
N56 Y-0.1249 B-90. F2199.77
N57 Y-0.1245 B-90.562
N58 Y-0.1232 B-91.155 F2038.921
N59 Y-0.121 B-91.756 F1898.811
N60 Y-0.118 B-92.342 F1771.322
N61 Y-0.1142 B-92.902 F1650.931
N62 Y-0.1096 B-93.448 F1537.781
N63 Y-0.104 B-93.984 F1435.427
N64 Y-0.0977 B-94.49 F1340.099
N65 Y-0.091 B-94.947 F1247.875
N66 Y-0.0841 B-95.352 F1154.939
N67 Y-0.0762 B-95.74 F1061.911
N68 Y-0.0676 B-96.104 F969.335
N69 Y-0.0584 B-96.427 F873.415
N70 Y-0.0491 B-96.696 F770.169
N71 Y-0.0396 B-96.914 F655.659
N72 Y-0.0297 B-97.087 F533.332
N73 Y-0.0195 B-97.212 F403.546
N74 Y-0.0095 B-97.285 F260.375
N75 Y0. B-97.309 F95.08
N76 Y0.0095 B-97.285
N77 Y0.0195 B-97.212 F260.375
N78 Y0.0297 B-97.087 F403.546
N79 Y0.0396 B-96.914 F533.332
N80 Y0.0491 B-96.696 F655.659
N81 Y0.0584 B-96.427 F770.169
N82 Y0.0676 B-96.104 F873.415
N83 Y0.0762 B-95.74 F969.335
N84 Y0.0841 B-95.352 F1061.911
N85 Y0.091 B-94.947 F1154.939
N86 Y0.0977 B-94.49 F1247.875
N87 Y0.104 B-93.984 F1340.099
N88 Y0.1096 B-93.448 F1435.427
N89 Y0.1142 B-92.902 F1537.781
N90 Y0.118 B-92.342 F1650.931
N91 Y0.121 B-91.756 F1771.322
N92 Y0.1221 B-91.448 F1898.811
N93 G00 Z1.6

N95 M05
N96 M09
N97 G90 G00 Z400.
N98 G00 B0.
N99 M02

Thank you for the quick solution!

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

HASSAN.ALI48H8K — Fri, 17 Jun 2022 10:05:33 GMT

i have same problam my machine is Doosan puma my toolpth is 2d addaptive .

Re: 4th Axis Wrapped Toolpath Feedrates Too Slow

bob.schultz — Tue, 21 Jun 2022 14:35:08 GMT

Hello @HASSAN.ALI48H8K, please take a look at the following thread. The suggested change to the post is towards the end of the thread and explains the change to the Doosan Mill/Turn post to get combination FPM/DPM feedrates output instead of pure DPM feedrates.

https://forums.autodesk.com/t5/fusion-360-manufacture/4th-axis-rotary-problem-every-line-feedrate-and-terribly-slow/m-p/11237693#M123462