What is a surface normal?

[Greg_J]

What is a surface normal?

 

Where do I find it when I'm selecting my surface in a multaxis toolpath more specifically parallel cuts toolpath.

 

And if it's so important for a toolpath why don't they even define it in the Matercam help?

 

TIA,

Greg

[heavychevy2155]

Its the relationship of the front and the back of the surfaces. They all need to be facing the outside of the part to drive the tool properly.

[Greg_J]

So if I have a U shaped surface and it keeps creating the tool path on the inside of the U instead of the out side of the U I am cutting the surface by rotating my A axis in my VMC. I've made the program before slightly different and I had no issues with what side it cuts on, maybe I was just lucky with the surface.

 

Is there away to tell it to switch what side to cut on?

[YoDoug®]

There is a button in the edit drop down menu for changing surface normals.

[George Hardwick]

Greg.

 

The surface normal can be thought of as a vector that points away from the surface at a 90 degree angle all round. The direction of the normal can be and often is, different for every position on the surface The normal is used for certain creation, manipulation and machining operations.

 

While the normal is not continuously displayed, whenn shading is not active the side of the surface the normal points away from is a solid colour. The other side appears dull grey. The direction can be flipped using the Modify, Normal function.

 

Copied from Mastercam Handbook.

 

George.

[Chris Rizzo]

Before machining any surface model, it's a good idea to use Analyze > Test surfaces solids > test surfaces. And have normals and small surfs turned on. Can save you some head scratching later if the model has issues.

[Greg_J]

Thanks guys. That's exactly what I was trying to find. I'll be adding "set normals" to my toolbars.

 

It seems a bit odd that anything regarding a toolpath is usually set inside the operations manager, inside each program or it prompts you when creating the program. But for surface normals you have to change it externally.

 

Try typing it into the help section it's not very forth coming, imo.

[Guest SAIPEM]

Its the relationship of the front and the back of the surfaces. They all need to be facing the outside of the part to drive the tool properly.

 

 

INCORRECT!

 

The surface normal vector, often simply called the "normal," is a vector perpendicular to a given point on the surface.

Surface normals exist on both sides of a surface face.

 

Mastercam simply wants you to determine which side of the surface you are working with.

[Guest CNC Apps Guy 1]

Surfaces get less atteention these days due to the proliferation of Solid Modeling.

Think oof the surface normal as defining the inside and outside of the skin. The defined color is the outside, the inside is grey. Like SAIPM said though, it's used for what side of the skin you want tto cut.

 

 

[Greg_J]

I primary use solids but I'll make surfaces from my solids and extend or modify the surfaces for my machining needs.

 

I don't see the grey they you've been talking about. If select the surface it all goes yellow both sides and if it's not selected it is the colour that I made it on both sides.

[Mick]

I primary use solids but I'll make surfaces from my solids and extend or modify the surfaces for my machining needs.

 

I don't see the grey they you've been talking about. If select the surface it all goes yellow both sides and if it's not selected it is the colour that I made it on both sides.

 

The "back" of the surface is gray in unshaded mode.

[Richard Thomas - Mastercam UK]

And if it's so important for a toolpath why don't they even define it in the Matercam help?

 

I typed "normal" into the Mastercam Help Index and the second result did actually give a definition of a surface normal... now it could have been written a bit more clearly, but it is there.

 

(it's in the description for the Set Normal command/ribbon bar)

[MLS]

May be somewhat of a tangent, but now I am curious.

 

 

Does Mastercam now drive the solid model independent of how the surface on said model is defined?

 

Take a flowline toolpath for example. If the the surface of the model is defined by curves(isoparms) then doesn't the toolpath follow said curves?

 

In my experience there are circumstances where even creating surfaces from a solid model results in an inverted surface normal and very often skewed isoparametric definition relative to the part.

 

I am a few versions behind however, just curious as to driving the solid necessarily negates the need for modifying or rebuilding surfaces due to normals/isoparms etc.

[BestMastercam]

INCORRECT!

 

The surface normal vector, often simply called the "normal," is a vector perpendicular to a given point on the surface.

Surface normals exist on both sides of a surface face.

 

Mastercam simply wants you to determine which side of the surface you are working with.

 

[Greg_J]

When it comes to creating certain toolpaths, in the prompt box it tells you to "pick a surface and watch your surface normals".

 

Do a search in the help for surface normals and you get nothing.

 

Why ask for something if you don't define it? or even have a way to check the normals when your picking the surfaces.

 

You have to go into another function to check the normals, makes no sense.

[#Rekd™]

Greg,

 

As far as I know the "Surface Normals" are the green arrows, watch the direction they are pointing in. Click on the arrow to reverse.

 

At least this is what I was taught at In-House.

 

Good luck.

[Tyler Robertson]

If you are doing work with a lot of surfaces, or a lot of trim work - you really need to check out Moldplus 5-axis toolkit. Automatic surface normal setting, surface trimming and shelling options, and click/drag tool path and vector editing. It is very useful for 5-axis trim work, waterjet, laser etc. Saved my butt a bunch of times

[Teh Bear without Brains kinda idiot]

Does Mastercam now drive the solid model independent of how the surface on said model is defined?

~~~~~~~~~~~~~~~~~~~~~~

yes ,but not Flowlines tp.

[Besty™]

If you are doing work with a lot of surfaces, or a lot of trim work - you really need to check out Moldplus 5-axis toolkit. Automatic surface normal setting, surface trimming and shelling options, and click/drag tool path and vector editing. It is very useful for 5-axis trim work, waterjet, laser etc. Saved my butt a bunch of times

 

How about multi-axis surfacing? Would Moldplus be any benefit there?

[Tyler Robertson]

How about multi-axis surfacing? Would Moldplus be any benefit there?

 

not as much as trimming, but it does have some handy surface fixing tools, like "Auto-Trim" which can join bad surfaces, the Auto-normal flips all normals to the "outside" of the part. Change UV direction can change Flowline directions and avoid some of those flowline error problems in badly surfaced parts.

 

http://www.moldplus.ch/5axiskit.htm

 

because the Create Curve 5 axis geometry is all done through clicking and dragging on the screen, you can use it to create line vectors for tilting the tool in tough to reach areas.