Rotary Feed Rate

[TonyL]

Hello,

 

I am manually programming a simple B axis rotatation and am wondering if there is an easy formula to figure out my feed rate from the linear feed rate. All I want to do is feed to position in Z @ 25 IPM and then rotate 360 degrees but at that feed rate the table is barely turning.

 

Any help would be great.

 

TIA

 

Tony

[TonyL]

Anybody have any experince with this?

[PeterM]

Tony,

Rotary feed is usually expressed in degrees/second

therefore the rotational rate will vary according to the diameter that the tool is rotating about the B axis

 

Dia x PI =C, feed rate per minute = f

 

(C/f)*6 = deg/second

 

I'm no math wiz but I'm pretty sure that this will work for you.

[YoDoug®]

What type of machine and control. It sounds like your getting B axis moves in deg/min. At that rate it will take approx 14 min to do a full 360 deg.

 

There are two ways to fix this.

1. change yoour post/control def to deg/min.

2. change machine settings to unit/min for B axis.

 

Need more info

[TonyL]

The machine is a Makino A-66 with a pro three control. I found a converter when I serched the forum and at my diameter of 12.795 it came up with a feed rate of 224 deg/min(based on 25 IPM linear feed rate).

 

Does the B axis automaticly use deg/min or do I have give it a command? There is a G95 "feed per rotation" command in my G-code list. I tried it both ways in MDI(G94 feed per minute & G95) and couldn't see much of a difference by eye in the speed of the table.

 

Any Ideas?

 

Thanks

 

Tony

[YoDoug®]

When you use the G94 feed/min there is a variable that has to be set to tell the control what Dia you are using.

[TonyL]

I Think that G94 is the default value, thats what the other machines are set at. Do you know what that varible would be?

[Guest SAIPEM]

quote:

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When you use the G94 feed/min there is a variable that has to be set to tell the control what Dia you are using.

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That method is only useful if you have a constant diameter and depth of cut.

 

For 5-axis rotary table programming, the value of the part radius is the length of the 3-D vector from the center of rotation to the tool tip.

 

By using this method you can properly calculate the DPM feed for each rotary move.

 

The only other option is using Inverse Time Feed G93.

 

G95 is Feed per Spindle Rev

 

Mike Lynch has a useful macro for calculating DPM at the machine during runtime.

http://findarticles.com/p/articles/mi_m310..._75/ai_97892437