Sunday, November 28, 2010

3D Milling of a human face

I've been wanting to do this for a while after my first failed attempt. Though I've not been into my shop for quite a few weeks, some time was spent on my notebook applying different features to the 3D head forwarded to me by jrmach of Bobcad forum.  The object is not to mill out the whole head, which I do not have the necessary knowledge at this point to use the 4th axis correctly.  It is to have a go with just the face.  The decision is to only mill out the 1st 10mm from the tip of the nose to experiment with the different features provided for in BobCadCam.  The Z-Level Rough was use to remove bulk of the material (wood this time for ease and speed of the job) followed by Slice Planar.  Cut amount in Slice Planar was set to 0.2mm to try to capture as much details as possible but I'm not able to match up with a smaller diameter cutter; A 6mm ballnose was used with 3mm radius.  Roughing was done with a 1/2" endmill.

Some pics:

Roughing out with 1/2" endmill

After finishing off with the 6mm ballnose

Short video showing the 6mm ballnose at work:

I notice during the milling process that the spindle was almost at the end of the Z travel. It was scaringly close.  Thank God that I decided to go only for 10mm from the surface (z = 0).  Can't imagine what will happen to my mill if I went for 15mm...  I've ordered a precision toolplate with cam type fasteners from Hightech Systems.  This will raise up the work by the thickness of the plate.  From the vpost tracking, it has arrived in Singapore yesterday and should be delivered to me on Monday.

A short video of that:

I also ordered an ER32 holder, some collets, and an ER16 (3/4-16) adapter with this shipment.  Hope these are the last I bought for the hobby this year.

Sunday, November 7, 2010

8-Direction Vertical Milling Column Upgrade - Done!!!

Little time in the shop resulted in no updates for the past weeks.  With the market slowing, I don't know why I'm still so busy.

The column upgrade was finally completed with slight modification to the length of the leadscrew.  As mentioned in my previous post, rotating the circular clamping disk didn't allow the vise to clear the disk.  I bought the column spacer to provide the clearance required.  But the spindle is lifted so high that it couldn't get down low enough to do any useful work.

This seems to be the max the spindle can go down to.

I saw that the leadscrew's end was "tucked" inside the clamping disk and realized that I need to shorten the screw a little.  So out came the Proxxon vise.

Sawing off a short section of the leadscrew.

A little too short but its working fine

Tramming came next.  Roughly getting into position:

Using DTI to get the column square to X and Y axes:

The rectangular piece is the Proxxon parallel

Best I can do for this

After tramming, I tried to "flycut" with an endmill held in the ER16 collet.  The result was good as I can get to 2 decimal places accuracy (in mm).  I've never gotten so close.  Rather happy with the result of this upgrade.  The 8 direction column makes tramming much easier than my previous setup.  Should have bought the 2010 mill right at the onset.

Further milling revealed that I may have a problem with my mill slipping out of the ER16 collet during cut.  I changed to an endmill holder and the problem went away.  Need to solve this as the ER16 way of holding tools is the most convenient to me.  Anyone with suggestions please share.