Interesting Aerofoil Platforms 1

[alanblackwell]

Morning Brainics,

I have an issue and I'm hoping one of you smart people can help me out.

I have a turbine blade to produce, this turbine has awful platforms, (coloured red).

I can cut the aerofoil, But the platforms are causing me a headache.

Please can somebody point me in the right direction.
I'm using version 7.5

Cheers
Alan

 

[MickyV007]

Can you describe what the cross curves are, are they depending on on some other equation?
You have two good curves when looking in the z-axis but the shape in the x-axis not what you want?

Best regards,

Michaël.

NX7.5.4.4 + TC Unified 8.3

 

[alanblackwell]

Hi Mickyv007,

Thanks for your response,
I think my first post is mis-leading,

This is the model I recieved from the customer, (some features have been removed).

I want to manufacture the platforms, (RED).

I know the platforms are messy, but thats what the customer requests.

Cheers
Alan

 

[bigguy136]

Not to get off topic but I program for a 7AX grinder (using T cutters as grinding wheels) only. I want to learn how you think when programming 3/4/5AX mills ect. If you have a solution to this, would you post the NX file so I can see what you did?

 

[alanblackwell]

Hi guys,

I posted a few days ago.

I really am stuffed when it comes to manufacturing these platforms.
Ideally i would like to use the aerofoil as the drive surface & cut the platform spiral style.

I can cut the aerofoil in this fashion, but when the tool reaches the platform, the stepover is to large, due to the drive surface/check surface intersection curves generated.

Which manufacturing cycle do you think would work
What drive condition should I use
Etc....


Thanks in advance
Alan

 

[alanblackwell]

Come on guys,

Somebody must know how to do this.

I really am stuffed on this issue, any input would be great.

Yours going bold swiftly.

Alan

 

[bongoman]

Variable axis - Surface Area. Do you have 5 axis? Tilt tool axis and spiral inward. Or use a lollipop cutter with 3 or 4 axis.

 

[wmalan]

Alan,
If you could post a couple views of the blade, I can look at it tonight at home. I'm at work (no internet here at work, only Blackberry). I've done several types of platforms myself on single blades.

--
Bill

 

[alanblackwell]

Bill,

Thanks for your post,

Theres a parasolid file attached to this thread.
would that be ok?

Alan

 

[wmalan]

Alan,

Sorry but I can only view images but I think that might be enough.

 

[alanblackwell]

ok,

I have attached a couple of screen grabs,

my status:-

I have been machining single blades for 4 years.
I machine blades on a 5 axis Starrag machine.
The software I use can only handle revolved platform surfaces.

The platform surfaces on this blade are chaotic surfaces!

I know how I would like to cut the platforms,
I have average knowledge of NX 7.5, but I can't get nx to cut these 2 platforms.

Ideally I would like to drive around the aerofoil in a spiral cutting the platform outside to inside.

Please reply

Alan

 

[wmalan]

Rough some clearance on the blade. Next, machine the platforms using Variable contour- Streamline with the tool projection along the stacking axis (c'line of the blade). You can then set a scallop or steppover projected on the hub and shroud faces (separate operations). Sometimes I use toolaxis Interpolate to achieve the proper tool axis as it transitions around the leading & trailing edges to keep the tool from cutting dead center on the tip. Does this help?

--
Bill

 

[wmalan]

Edit: Alan, the platforms are the drive surfaces.

--
Bill

 

[alanblackwell]

Hi Bill,

Thanks for sticking with me.

I'm doing ok as you will see from the attached jpeg.

But:-

I'm having issues with the 'tool axis' selection drop down box.

I have no idea which to select, I've tried various options, but all options seem to shoot the tool into space.

Any input would be great.

Alan

 

[alanblackwell]

JOB DONE,

I set the tool axis to revolve around a line, then tip the tool about 30 degs.

Thanks for your help Bill,(wmalan).

You deserve the stars.

Alan

 

[wmalan]

Alan,

Glad to help!

--
Bill