Walls are getting thicker

[pernilla]

Hi.

I need a strategy for a problem I'm about to have...

A part that has a general tolerance of 0.2 (mm) profile of a surface, has now been changed in wall thickness. (+0.05 mm on every wall)

The problem is they're NOT sending a new CAD model, and I suspect it'll be difficult to get all the profile of a surface within tolerance when the CAD model is no longer nominal (except in Z axis, height has not changed).

I can't really show the part so I'll just show a picture of a corner to give you an idea of how it looks, and there are a lot of walls, inner walls, angled walls, radius...


wallthickness.png

I realise the tolerance is more than 0.05 and that the walls should still get within tolerance but this is not going to change back, the walls are thin so there will be variations, and we're going to produce a lot of these, so I want to do this the right way. I just don't know what the right way is here...

Does anyone have any idea or solution to this?

[Matthew D. Hoedeman]

F9 each point and add the 0.05mm stockthickness.

OR, if they will allow, change the tolerance to reflect the new stock thickness. Instead of +/-0.1 use either +0.05/-0.15 (or +0.15/-0.05, whichever is needed).

OR

SHOW ALL PARAMETERS, then search & replace all "THEO_THICKNESS = 0" to "ACTL_THICKNESS = VTHK"

Then, at the top of the program, add a variable for VTHK=0.05

[pernilla]

The F9 option could probably work, I just change the nominal then? But I don't know if I can calculate the angled walls and the radii.. isn't that complicated?

About the change of tolerance, I'm quite certain they will not allow it.

What does "THEO THICKNESS" actually mean? I mean, why is it "= 0" before I'd change it? The thickness is 0,8 in the CAD model...

[KIRBSTER269]

I don't know if your familiar with Transform, but you could bring in a second model and shrink the model a bit, its tricky, make sure your just Transforming the 1 CAD model only. I use the Caliper to get it to the size I want. As you see just wanted to change that width in the Y direction, after I get it to the size I want, I will align the 2 CAD models and of course move it +.005 in the Y direction. As you see I had to downscale it .9966 in the Y direction to get .010 from original size. Problem with this, When I don't get the number I want, I have to CANCEL Transform, so it doesn't save the changes.until I get the right number than I hit OK
Capture.JPGCapture2.JPG

[pernilla]

That's probably a good strategy. It seems like that's the way to solve this, but I highly doubt I could ever get it to work right. It seems very difficult and I've never done anything like that before.

For starters I haven't even used the caliper tool before. And you've aligned that second CAD model next to the first one... Why not "inside" it? How does the aligning work when you've only got one physical part?

And how did you know you had to downscale it .9966 to get .010 from original size? Did you calculate it somehow? And by scaling it in only Y axis, won't it get a mis shape?

Sorry about all the questions... you don't have to answer all of them.. I'll go have a look in the help section now.

[pernilla]

I'm going to solve this problem by changing T: Nominal +0.05.
Since I'll be making a new program anyways, it won't be much trouble at all.


Thanks for all your suggestions, it is very much appreciated.

[KIRBSTER269]

No problem with all the questions, and yes I would put the second one inside the other one, I just stacked it like that for visual, I also changed the color on top one, again, just for visual. As I stated above, I would align the parts as soon as I got the correct size, As far as how did I get .9966? Trial and error, the reason I use Caliper, The Caliper is just a Reference to see the size, just click on one surface to the other surface and make sure you're in the correct axis and it will tell you the distance.

[KIRBSTER269]

Oh and I have said this time and time again, Don't get lost with the CAD model, When you create a program, Based off of the CAD model (the ONLY perfect Part) You are creating the parts MATING part. Once your program is made, The CAD MODEL is worthless, it's just a pretty little picture on your computer. Changing the size of the model won't change your program, unless you actually changed features inside the program. You wanted to change the 2 sides, which the way I showed in the pictures, you would be able to click on the new surfaces. This is not easy if you are not familiar with it, I highly suggest playing with it before you use it.

[pernilla]

Thanks! I'll definitely play with it before using it!