Help on procedure for machining this part

[turboboy]

Im new to machining. I have a haas VMC and want to machine a part like the one in the picture. Whats the easist way to hold it. I was thinking machining the bolt holes for the caps. Then the bolt holes in the end of the riser body first. Then bolt the caps to the riser body and profile the whole part to shape. Anyone have any ideas to help. I dont have 4 th axis if that matters.
Thanks

[tobyaxis]

What are the dimensions L,W,H, Applicalion, and Material to be machined?

What type of work holding devises do you have, Kurt Vise, Fixturing Material and Hardware?

Lots of ways to skin a cat.

[turboboy]

Toby the total length will be around 8" width is 1.5" height is 1". I have 2 kurt vises and also selection of alum jaws i have been using.Its 6061 alum.

thanks

[HuFlungDung]

Your plan sounds okay to me. Depending on the necessary roundness and the potential interchangeability of the half shell caps, you may have to take a lot of care to face the main body piece exactly to theoretical length, because the tolerances will start to stack up from there.

As soon as you bolt the end caps on, then you will most likely have to locate from the end of one of the end caps, which means that the end caps must be quite accurately made in height, too, to ensure that the location of the holes is a true half split.

[keebler303]

what if you mill the large holes as oblong in one piece. Then drill your bolt holes. Then cut the thing in three and clean up the edges. That would insure your bolt holes would line up and if you made the circle oblong you would know how much to face it down so it was a perfect semicircle.

Matt

[widgitmaster]

With two kurt vises and soft jaws, you can hold the blank bar in the 1st vise, mill 50% deep of one side, then reverse contour the jaws in the 2nd vise to hold the machined part upside down to machine the remaining 50%

Each cycle start is one finished part minus the end caps!

Just a thought!
Eric

[wildcat]

Did anyone else notice that the parts are not flat but instead zag over a little on the end that is not holding a piece of round in the picture? Widgetmaster - maybe that is what you were getting at... I did not quite follow your suggestion.

[widgitmaster]

From the image you provided, I gathered you needed to make 3 parts! The connecting rod and the two end caps.

The procedure I described will work on a CNC machine with two vises mounted on the table, each vise having soft aluminum or steel jaws.

The objective is to make the 3D contour on the top half of the connecting rod in the 1st vise, then move the part to the 2nd vise and finish the opposite side of the 3D contoured part.

The same procedure will work for the end caps, and you can do two caps per vise!

Lastly, the center bores should be done after assembly, to ensure they are symmetrical, parallel, and concentric to each other.

3D contours are small potatoes for CNC machines, and most people over complicate things because they don't see the tremendous power they have!

From another perspective, if the same parts were made on a manual Bridgeport mill one at a time, the procedures would be many and each surface would be a separate operation! That's a long slow process, to say the least!

But you did specify the use of CNC!

Eric

[widgitmaster]

To clarify further, you would need three G-Code programs for the connecting rod!

1st Code is for the top side of the connecting rod in vise #1
2nd Code is for the reverse contour of the soft jaws of vise #2
3rd Code is for the bottom side of the connecting rod in vise #2

[nervis1]

Don't forget that is not a complete circle you need to face off a bit like .03-.05 off of each half circle clamp surface (where the bolts protrude and thread) so it will be able to clamp down on the bar. Otherwise there will no clamping.

Ask me how I know this (thankfully I only ran off two parts before I figured this little detail out )

[wildcat]

Could the connecting rod and clamps be machined in one piece and then parted? The width of the bland should take enough away that the clamp will actually clamp.

I don't know anything about making 3D contours - if I can't cut around the outside I can't do it. Going to have to learn about that though.

[tobyaxis]

Originally Posted by wildcat Could the connecting rod and clamps be machined in one piece and then parted? The width of the bland should take enough away that the clamp will actually clamp.

This is what I was thinking.

Lots of ways to skin a cat