# Machsupport Forum

## G-Code, CAD, and CAM => G-Code, CAD, and CAM discussions => Topic started by: Tef9 on May 17, 2008, 12:41:14 PM

Title: Double taper
Post by: Tef9 on May 17, 2008, 12:41:14 PM
Hello,

I am trying to program a double taper in G-code.  I am having some difficulty understanding how the angle works.  I can make one sided taper like the wizard, however I want to go back the other way like this :

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The decending taper would be varying in size and shape eventually but for the moment I would like to be able just to mirror the existing taper.

Thanks,

Andy
Title: Re: Double taper
Post by: Graham Waterworth on May 17, 2008, 03:35:26 PM
To create a taper the X & Z must be commanded on the same line :-

e.g.

G00 X5. Z1. G97 S1000 M3
G01 Z0 F.1
X15. Z-5. (produce a taper @ 45 degrees)
X5. Z-10. (and back down the other size)
X20.
G00X50. Z50.
M30

Graham.
Title: Re: Double taper
Post by: Tef9 on May 17, 2008, 03:40:44 PM
Hi Graham,

Thats great, How do I set the angle?

Thaks,

Andy
Title: Re: Double taper
Post by: Graham Waterworth on May 17, 2008, 06:13:54 PM
SIN of the angle.

e.g.

If taper is 20mm long @ 25 degrees included angle and the small dia is 20mm at Z zero then :-

X=20+((SIN(25/2)*20)*2)  i.e. 20+(((4.3287)*20)*2)
Z=-20

G00 X20 Z1.
G01 Z0 F.2
X28.657 Z-20.

Graham.

Title: Re: Double taper
Post by: Tef9 on May 18, 2008, 05:11:01 AM
Hi Graham,

Thanks for this however is it possible to calculate using the xstart and xend and the zstart and end, without having to know the (small?)diameter of the job?

With the wizzard for taper how does it facter the angle you imput?

Also one last question is it in radians or degrees?

Thanks,
Sorry for the questionaire

Andy
Title: Re: Double taper
Post by: Graham Waterworth on May 18, 2008, 05:59:31 AM
Its just basic trig.  its all in degrees, you have to have a starting point somewhere in X and Z.

You can use the biggest dia or the length and an angle. the main point is to work out half the included angle and the length, then double it for diameter.

I do not use the wizards so I can not help you with them.

Graham.
Title: Re: Double taper
Post by: Tef9 on May 20, 2008, 01:44:21 PM

Hi Guys,

Thanks for all the advice so far however below is my code:

How can I create an angle and control depth of cut, also when I run this it does not produce a double taper it produces an hour glass shape.  Is there any way to change this.  I am using a sherline lathe with the mach 3 sherline profile (metric).

Thaks for your support

Andy

G18 G21 G40 G49 G90 G94 G80
M3
F65
G0 X0
G0 Z0
G0 X0
G1 X-0.5 Z-26.25
G1 X0 Z-52.5
G0 X0
G0 Z0
G0 X-0.5
G1 X-1.0 Z-26.25
G1 X-0.5 Z-52.5
G0 X0
G0 Z0
G0 X-1.0
G1 X-1.5 Z-26.25
G1 X-1.0 Z-52.5
G0 X0
G0 Z0
G0 X-1.5
G1 X-2.0 Z-26.25
G1 X-1.5 Z-52.5
G0 X0
G0 Z0
G0 X-2.0
G1 X-2.5 Z-26.25
G1 X-2.0 Z-52.5
G0 X0
G0 Z0
G0 X-2.5
G1 X-3.0 Z-26.25
G1 X-2.5 Z-52.5
G0 X0
G0 Z0
G0 X-3.0
G1 X-3.5 Z-26.25
G1 X-3.0 Z-52.5
G0 X0
G0 Z0
G0 X-3.5
G1 X-4.0 Z-26.25
G1 X-3.5 Z-52.5
G0 X0
G0 Z0
G0 X-4.0
G1 X-4.5 Z-26.25
G1 X-4.0 Z-52.5
G0 X0
G0 Z0
G0 X-4.5
G1 X-5.0 Z-26.25
G1 X-4.5 Z-52.5
G0 X0
G0 Z0
G0 X-5.0
G1 X-5.5 Z-26.25
G1 X-5.0 Z-52.5
G0 X0
G0 Z0
G0 X-5.5
G1 X-6.0 Z-26.25
G1 X-5.5 Z-52.5
G0 X0
G0 Z0
G0 X-6.0
G1 X-6.5 Z-26.25
G1 X-6.0 Z-52.5
G0 X0
G0 Z0
G0 X-6.5
G1 X-7.0 Z-26.25
G1 X-6.5 Z-52.5
G0 X0
G0 Z0
G0 X-7.0
G1 X-7.5 Z-26.25
G1 X-7.0 Z-52.5
G0 X0
G0 Z0
M5
M30
Title: Re: Double taper
Post by: Graham Waterworth on May 20, 2008, 02:47:16 PM
make sure you have CV turned off in config.  CV and turning do not go well together. Set config to exact stop mode.

Graham.
Title: Re: Double taper
Post by: Tef9 on May 20, 2008, 03:32:28 PM
Thanks, however I turned that to exact stop mode and it still turnes inward rather than out. :-[

Any other thoughts?

Thanks,

Andy
Title: Re: Double taper
Post by: Graham Waterworth on May 20, 2008, 06:12:04 PM
Post a picture with some dimensions of what you are trying to achieve.

Graham.