Machining Question

[JG]

Hi All,

 

I would like your opinion on the best method to finish machine the following....

 

slot approx .8 x 1" x 3.9" deep

mat'l is alum.

location of the feature requires 14" of reach using shrink fit tooling. after drilling and Z plunging as much as I can would you helix the finish path or step down then xy each level? tolerance is .002 total.

 

thanks for your input!

 

jg

[iowajim62]

Slot Mill Toolpath with ramping would be my first approach method.

[JG]

thanks for the input.

 

my first choice was/is ramping....however i'm feeling resistance from others who prefer the drop, xy method. I thought this would be a great place for real world advise.

 

thanks again,

[High Sierra Plastics]

On steel the drop plunge method has sometimes caught the end mill on the cusps and break. I don't know about alum. though.

[dprovost71]

I would try the ramp. You might want to lighten up on the ramp angle. I think the default is 3 degrees.

[Colin Gilchrist]

Cutting with a Ramp/Helix will keep the tool engaged during the cut and transfer some of the cutting forces up into the spindle in Z. It will also help prevent a dwell mark in the slot wall where the tool transitions in and out of the cut...

 

My vote is ramp it!

 

HTH,

[Justin Beebe at Folsom Tool]

On deep slots I like to rough the slot leaving material on the wall and then ramp it with contour ramp to finish.

[Superman]

1. Drill or interpolate ends out to correct size (+plus tolerance)

2. plunge slot excess

3. rough contour ( ramp method min. finish allowance )

3. finish sides ( z-level not ramp )

( finish tool relieved at the back- flute length 0.50" longer than stepdown- small blending rads on flute ends for z-level mismatch)

[JG]

thank you all for the input.

 

Superman,

 

would that method apply if the slot only had about .060 of land between the holes? (.060 imperial)

 

thanks,

[Slydman]

After roughing process.

I would finish the wall on 2d contour no ramp multiple Z depth cut

with a lead in/out

w/perp-line .050

w/arc rad 400% sweep 2deg

using enter/exit at midpoint in closed contour

 

That will make the entry and exit very smooth.

I made a lot of part for microwave where no mark are allowed.

For aluminium it came out great

[Superman]

The ends are finished 1st so that the tool has no deflection when changing direction while roughing or finishing

 

Hole centres can be any distance apart on a straight or curved slot