LOLLIPOP SURFACING NEG DRAFT

[Mark Tower from C&H Machine]

Need a little help here. we have been told that

flowline surfacing is the only way to surface a neg draft. so i have tried to generate 3 different

times with 3 different results. any tips you may offer please do..

[Roger Peterson]

You can also do an undercut with other surface toolpaths, parralell, if you set your tplane to top and cplane to perpendicular to the surface. It would probably be best if you sent it in to your reseller or post the file on the ftp site.

 

good luck

[Scott Bond]

quote:

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we have been told that

flowline surfacing is the only way to surface a neg draft.

---

Please give a little more info,post some of the surface on the ftp. There are many options, in all versions

[Guest CNC Apps Guy 1]

When cutting undercut surfaces, the post does not really need to be considered. The last part I did where I had to undercut about .125 per inch of depth. I used surface finish flowline, turned off all the gouge checking, used Direction to start the tool off the surface and in the gap settings - Smooth to allow the tool to transition on and off the surface so as it needed to retract, it would clear the part.

 

So in a nutshell, it is very possible to cut negative draft surfaces. It just takes some learning time and a boss that's willing to spend a few extra dollars in tooling to save a few hundred (at least) in un necessary setups. Hope that helps. And as always, you can always call your local Mastercam reseller for extra help.

 

JM2C

 

[ 08-12-2002, 07:52 PM: Message edited by: James Meyette ]

[Trevor Bailey]

Another "down & dirty" method I have used, which works pretty well, is change "planes" to the respected geometry. Create a parallel or flowline toolpath onver the area needed. Using backplot, make the toolpath lines geometry and save them. Now go back to your original "gview". Now you can use the 3d contour toolpaths. It will take a little playing, such as changing compensation from tip to center of tool and maybe a little geometry editing. Other than that, this method works really well, especially when you have tried the standard toolpath's such as James mentioned. Sometimes these path's on undercut surfaces will retract in the worst places resulting in a gauge. No matter what setting you. It all depends on your geometry. This is one of the best things about MC, you have so much flexibilty to get the job done.