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Topics - kvom

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CamBam help (General usage) / Plugin icons on toolbar
« on: February 27, 2021, 13:30:47 pm »
Moving to a new computer after many years, I added the threadmill plugin.  Its icon appears on the machining pulldown but not on the toolbar, and I can't remember what I need to do to put it there.

Bug Reports / Spiral leadin with cut width.
« on: July 12, 2020, 22:16:08 pm »
I needed to machine an outside profile using a cut width greater than the tool diameter.   With Spiral leadin I am seeing a clearance move at each depth increment.  Seems that the Depth First spec is not being followed.  No change with any of the optimization modes.

If I set the stepover to 0, the cut width is ignored, and the profile is machined.  I think this should generate a warning msg.

It's possible to do what I want by two Mops, which is what I ended up doing.

Feature Requests / 4th axis cam machining
« on: May 11, 2020, 14:39:45 pm »
I know that other CAM programs have ops for machining cam lobe profiles.  An idea I had was to draw the lobe in CAD, import to CB, and divide the polyline into multiple short segments.  I could then extract the points and write a Java program to move such that each segment between two points is horizontal with the tool touching it.  I haven't needed to machine a cam yet I haven't moved on this idea.

But then it occured to me that a plugin could be written to take as input a pointlist created by dividing the lobe polyline.  The output would be a straight line in Y with Z values equal to the distance from the center for each point and Y values equal to the spacing of the point.  Then an engrave Mop will follow the Z values as it moves in Y.  The output gcode would then be converted to A moves via the wrapper plugin.


How to's and tutorials / Work offset with CB
« on: May 06, 2020, 11:29:39 am »
I have a current project where I needed to drill a common hole pattern around 4 different other holes in a casting where these 4 hole coords weren't fixed by the plans.  It occured to me to use work offsets for each hole and run the single g-code on each.  So I measured the center of each hole as 0,0 using a different work offset.  Then I typed G54, run program, G55 run program.  Not something one needs every day as with CB one rarely needs work offset.

The distance in X,Y between a pair of holes is also determined this way.

Members Projects / Pointlist proves useful
« on: December 31, 2019, 13:29:45 pm »
I needed to turn this shape for a current engine build, where I had Solidworks model for the part.  Converted to DXF, adjust the outline, and created a pointlist along the curves with 50 thou spacing.  I was able to display the points and screen print them.  Then used a cutoff tool with DRO assistance.

Preliminary sanding with 80 grit got most of the steps out.

CamBam help (General usage) / Engrave doesn't follow polyline direction
« on: August 17, 2019, 18:59:19 pm »
When engraving multiple polylines with a single MOP, it isn't possible to control the direction via polyline reversal.  In my case, I was engraving scale markers on the side of a plate, and wanted the tool to descend outside the workpiece rather than plunging at the interior end.  The only solution I found was to have a separate MOP for each line with the start point moved outside the workpiece edge.

First time ever milling LH threads today.  For climb milling, a left hand thread should mill from the bottom upwards clockwise.  But I need to switch the direction to conventional in order to do so.

How to's and tutorials / Thread milling external on oversize stock
« on: July 27, 2018, 13:39:04 pm »
Yesterday I needed to machine an 8-32 thread on the end of some 3/16 stock.  To use a die I'd need to turn down the end of the rod to the major diameter of the thread.  But I realized that I could modify my MOP for 10-32 threads to take a couple of extra passes to hit the minor diameter of 8-32.  Worked like a charm.

I suppose the same idea could be applied to internal threads, but since one has to drill a hole first drilling the correct size is just as easy.

How to's and tutorials / Interpolating holes
« on: July 07, 2018, 23:01:26 pm »
The drill MOP does a fine job of getting large or non-standard diameter holes made, but what if the hole size  is more than twice the diameter of the tool?  One obvious way is to interpolate a smaller hole in the center and then either a second interpolation or an internal profile to finish.

A more straightforward method is to use the trochoidal pocket MOP.  When the pocket is a circle the toolpath generated is a spiral from the center out to the hole boundary.

CamBam help (General usage) / Plunge Roughing
« on: June 01, 2018, 20:03:52 pm »
Bob Warfield just published an interesting article on plunge roughing, where material is removed by plunging a tool into the work in series of overlapping holes.  This is very similar to chain drilling, and has some advantages.  First, MRR is typically higher than with almost any other type of milling.  Second, there is no need to worry about tool flexing/breaking since there's no side forces on the tool.  Finally, the Z axis is typically more rigid than other axes, so lightweight machines can use the technique advantageously.

To use this for a profile in CB, it's necessary to have a polyline offset from the target polyline by the tool radius plus roughing clearance.  I can generate this line in my CAD program, but whether there is a script in CB for this I don't know.  Once you have the line, the plunge points can be generated as a point list via the "Draw>Point List>Step Around Geometry" operation in CB.  One chooses the step distance according to the tool diameter.

For roughing a pocket, one uses the "Draw>Point List>Fill Geometry" operation, but again you need an inside polyline offset by the clearance.  However, in this case you might choose to explode the point list into individual points and delete those that are too close to the pocket edge.

Finally, code a drill operation on all of the points for either the profile or pocket.

Bug Reports / Stock size problem for Cutviewer
« on: May 08, 2018, 18:02:48 pm »
CB file with two parts.  Both parts have stock defines and part sizes are different.  If first part is disabled, g-code file still has stock/block lines with first part's stock dimensions if g-code is generated from Machining item.  If g-code is generated from the part then the stock is correct, but then the edit g-code function doesn't work.

CamBam help (General usage) / Open Poly
« on: December 28, 2017, 18:41:07 pm »
For whatever reason, the polyline in the attached file refuses to cooperate.  I have tried arc fit several time with increasing tolerances.  Very strange.

CamBam help (General usage) / Advice for vacuum chuck machining
« on: December 23, 2017, 21:30:07 pm »
My current project involves some profiles and holes on sheet. Materials include aluminum from 1/8 to 1/2 thick and acrylic 1/8 and 1/4.  The sheets are larger than is easy with a vise, si I've order a vacuum chuck from Pierce Workholding.  Everything involved needs to be a through cut eventually, but I can't do on with this chuck or the vacuum will "leak" out.  So I need to choose a target depth a little less than the material thickness. 

If anyone has done this successfully I'd like to know how much material you left to be trimmed off.  I do have a margin of safety since the aluminum comes with a tough plastic sheet stuck to the bottom, so as long as I don't cut that I can survive.  Similarly, the acrylic sheet has a piece of thin cardboard on the bottom.

Feature Requests / Minimize object extrema?
« on: December 07, 2017, 10:25:30 am »
I currently have a project whose outer boundary is very irregular.  In order to get it to fit on some standard stock material I had to rotate it by eye so that the Y extreme was (approximately minimized).  It occurred to me that a plugin could probably have done this easily.

Bug Reports / Moving multiple Mops
« on: November 26, 2017, 00:44:03 am »
Assume my Tree has 4 mops, 1-4.  If I select 2-4 and move them above 1, the resulting order is 4321 rather than the expected 2341.  Tested in V1.0R14

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