CAM - Chamfering holes with differing diameters in the same operation

[scotttyler2007]

Hello all,

First post to the forum.  I've been doing pretty good on my own so far.

The scenario is, I have a part the has multiple holes with differing diameters that all need to be chamfered.  I know how to do that easy enough.  Thats not the problem.

The problem is, I don't see any way to handle chamfering all the holes in a single operation and achieve the results that I want.  As we know a chamfer is a result of the chamfer width and the hole diameter, so applying a single chamfer operation to all holes with the same tool heights will not yield consistent chamfers accross all holes.

Why is this a problem?  The part is fixtured in a linear array of multiple parts.  Using separate chamfer operations for each hole diameter requires too much machine time.  So rather than fix it in post I'd like to know how to accomplish this in the CAM environment, since this is a scenario that occurs quite often for parts we machine.

A screenshot of the part in question is attached if that helps you visualize the problem.

Thanks in advance,

[Steinwerks]

Using a drill operation? Drill to chamfer width (not diameter) of .005 or so. Or use a chamfer mill and 2D Chamfer or 2D Contour.

[scotttyler2007]

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@atomkinder67 wrote:
Using a drill operation? Drill to chamfer width (not diameter) of .005 or so. Or use a chamfer mill and 2D Chamfer or 2D Contour.

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Thanks for the reply,

The problem is not that simple.  I'm currently using the drill operation to chamfer the holes in several drilling operations.  The reason for doing it this way is that the holes to be chamfered are not all the same diameter.

Look at it like this.  If I use one drilling operation to chamfer all the holes, that means I use one bottom height for the tool plunge depth.  This means that the major diameter of the chamfer is constant.  So some holes are chamfered to much and some holes not at all.

So I use a drilling operation for every hole diameter, each operation with a different bottom height.  There are 3 different hole diameters on the part, so I have 3 different drilling ops.  This produces much wasted machine time due to air cutting because the tool has to "back track" to the holes that it "missed" so to speak.  The chamfer widths are between .02"-.04", they arent edge breaking chamfers they are more like lead in's for other components.

If I have to use a 2D contour, I guess I will, but I just wanted to know if there was some secret way to merge the individual drilling ops to eliminate unwanted tool movement.

Thanks,

[Steinwerks]

Drill to chamfer width will not drill to the same depth for every hole.

[Steinwerks · Accepted solution]

Was on my phone earlier. This is HSMWorks but the toolpath is the same.

Setting your height "To Chamfer Width" will calculate a depth to leave you entered chamfer, all in one toolpath:

[scotttyler2007]

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@atomkinder67 wrote:

Was on my phone earlier. This is HSMWorks but the toolpath is the same.

Setting your height "To Chamfer Width" will calculate a depth to leave you entered chamfer, all in one toolpath:

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Thanks for the reply,

This is the solution I was looking for.  I wasn't aware of that option for bottom height.  I've never used HSM works before so i was not familiar with that option.  I guess I was blind to it because I just assumed that the selections were the same for all heights.

The method I was using before was to use model top for the bottom height, then offset it a certain amount to achieve the proper chamfer width.  Kinda dumb in retrospect 😕

Thanks for the solution,

[Steinwerks]

No worries! It takes a little getting used to, especially if you're new or coming to model-based toolpaths from 2D CAM. You can also use the heights to set a chamfer diameter (IE if the following drill is bigger than your spot drill) which takes all the fun math out of figuring out how deep to make that 120° spot drill go if you just want 1/4" spot.