CNC Milling

The needed Steps

A.
Prepare the 3D-model for
3-axis Milling (splitting and placing parts)

B.
Export file for a

- Roland CNC Milling machine. STL files
- Professional Industrial CNC Milling Machine.
  STEP or IGES files (occasionally STL aswell)

C.
Contact the CNC mill operator
if using the big 5-axis

Prepare the 3D-model

Export for the Roland CNC milling Machine

Export for the Professional CNC milling Machine

A. Prepare for 3-axis Milling (splitting and placing parts)

Correct Scale and Units
Size
Surface Normals
No Undercuts
Create Geometry if Layer Symmetry is used
Place parts on Z=0
Check Surface Normals and Under Cut again
Space between parts!
Check the needed Size
Export out the Milling File

The 3D-model usually needs to be adjusted and splitted before exporting it for 3-axis milling!

Correct Scale and Units

Do you have the right scale and units?

Measure known distances in your model - just to be sure
For IGES or STEP files always use mm
For STL use mm but ALSO communicate the choosen units (mm)! STL does not carry the information about m, cm, mm or inches! This can go terribly wrong if the milling operator is not clear about inches or mm...

mm or inches? Scaled as the actual size needed?

2. Size

- Small parts can be difficult to mill.

If you are doing for example small buttons they should not be high because that could possible mean that they loose while milling. Small is ok if not high at the same time. A possibility is to model some extra material and then manually cut it off after milling.

- Big parts might not fit into the milling machine. But then you could split it into smaller parts before exporting for milling.

Approximate max milling volume:

- 1. Roland MDX-40A: 300 x 300 z=50
  2. Roland MDX-50: 300 x 400 z=50
  3. Sahos 5-axis: 1500 x 2000 z=900 mm

Roland 300x300 z50mm

Sahos 5-axis 1.5x2 z0.9m

3. Surface Normals

Set all surface normals to point outwards from the object.

In Alias: Surface Edit > Orientation > Set Geometric Surface Orientation

In Rhino: Correct with ShowDir

In Alias: Correct with Set Geometric Surface Orientation

4. No Undercuts

The Milling Tool has to "see" all surfaces from a top view, Z-direction.
If Under Cut Areas is present then split your 3D-model into several smaller parts and glue them back after milling is done.

Use the Draft Angle Tool to find the Under Cut Areas

Alias: Surface Evaluation diagnostic shader

Rhino: DraftAngleAnalysis

Some times you might settle with a small area (Under Cut) that you need to manually grind to the correct shape after the milling...

In Rhino: Find Under Cut Areas with DraftAngleAnalysis

In Alias: Find Under Cut Areas with Surface Evaluation diagnostic shader

5. Create Geometry if Layer Symmetry is used

For Alias:

Select a Layer with Symmetry turned on
Select: Layer > Symmetry > Create Geometry

If Symmetry, Create Geometry

6. Place parts on Z=0

Put the parts flat on the X and Y-plane (Z=0)
And close to origo (0, 0, 0)

For Alias: Delete all Construction History and position the Green Pivot Point(s) so it´s easy to Rotate
For Rhino: Just use Rotate3D and Snap to the Grid
Place the objects Flat on Z=0

Pro tip:

3-axis milling machines only "See" straight down from a Top View! So you don´t need "hidden" surfaces as:

flat vertical areas
surfaces covered by other surface

Rhino: Flat on the Grid Z=0

Alias: Flat on the Grid Z=0

7. Check Surface Normals and Under Cut areas again (after split)

8. Space between parts!

The Milling tool needs space between the parts!

The big Sahos machine needs 6 mm more than the Tool diameter. If a 10 mm tool you need 16 mm space.

The small Roland machines needs about 120-200% of the tool. For a 5 mm tool you then need about 6 to 10 mm space.

Tip

Make a Circle and move it around the parts to check the clearance.

9. Check the needed Material Size

With more parts, does it still fit into the choosen Milling Machine? Check size in X, Y and Z direction
And remember to check the Z-height aswell! :)
The choosen tool set the max possible Z-height for your model!

X:a Space for the Milling Tool

The choosen tool, set the max possible Z-height

B. Export for

1. 1. Roland milling machine STL (see here below)
  2. Professional CNC milling machines STEP or IGES (see here below)

1. For Roland CNC milling Machines export STL files

Rhino STL export: go Here
Alias STL export: go Here

Roland Milling Machines from Rhino or Alias

Roland CAM-software

First time the SRP-player is started you must follow this PDF!

The "Roland SRP Player first startup.pdf"

Goto our server:
\\130.239.61.251\uid\Public\public_installs\SRP Player on LAB

If you copy the complete "SRP Player on LAB" folder and run "Install.cmd" you can also have this on your private PC 😀

Important first time setup!

2. Load the STL-file into the SRP-Player software

Always follow this video lecture: SRP video Lecture One
(Needed both for the MDX40A and MDX50)

A. Drag and drop .STL

If you need a Tool Changer and like to use the MDX50 machine you also need this video: SRP Lecture Two (Only for MDX50)

Go to: 4min 7sec into SRP Lecture One

B. Orient with Z up

Go to: 4min 33sec into SRP Lecture One

C. Faster cutting Time

D. Model with ANY curved surfaces

Check: "Model with many curved surfaces"
(Many should be ANY)

E. Cut top only

Go to: 5min 0sec into SRP Lecture One

F. Material (Red PU foam)

G. X and Y size a bit bigger then minimum (value)

These, X and Y, are not important, only for rendering purpose

Go to: 6min 30sec into SRP Lecture One

H. Z-height , add 2mm from the shown minimum

This gives 1 mm extra on all the top surfaces and forces these to be milled

Model placement: Center

Go to: 7min 35sec into SRP Lecture One

I. Create Tool Path

Go to: 8min 30sec into SRP Lecture One

J. Preview Cutting

Makes a rendering of how it will look after milling

Go to: 8min 55sec into SRP Lecture One

K. Toggle between Model and Rendering

Leaves a "skirt"
Inside radius
Missing hole

Go to: 9min 35sec into SRP Lecture One

Are your parts to close to each other?

Choose a smaller milling tool or
separate the parts in your source 3D-software (Rhino, Blender, SolidWorks)

L. Make sharp outside edges (no "skirt")

Let us lower the milling tool to avoid a "skirt"!

Go Back to Create Tool Path
Select Edit

Go to: 11min 2sec into SRP Lecture One

M. Check the present Mill Tool Size

Expand Roughing1
Select Milling tool
Note the size (here 3mm ball nose)

Go to: 12min 45sec into SRP Lecture One

N. Adjust down with value of Tool Radius

Roughing Tool Path

Select All (Depth)
Partial
Lower present value (-5mm) with the present size of tool radius (here 3mm)
-5-3 = -8 mm
Apply
Accept deleted tool path, Yes

Go to: 13min 33sec into SRP Lecture One

O. Adjust down with value of Tool Radius

Finishing Tool Path

Select All (Depth)
Partial
Lower present value (-5mm) with the present size of tool radius (here 3mm)
-5-3 = -8 mm
Apply
Accept deleted tool path, Yes
Close

Go to: 13min 57sec into SRP Lecture One

P. Create new Tool Paths

Go to: 14min 09sec into SRP Lecture One

Q. Preview Cutting

Go to: 14min 32sec into SRP Lecture One

R. Verify sharp edges

Go to: 14min 45sec into SRP Lecture One

S. IF not milling clean all around your model

Create new Tool Paths

Goto Create Tool Path
Edit
Under:
- Roughing1 and Finishing1
- Top Surface
- Modeling Form
Automatically
Apply and close
Create Tool Path

Go to: 16min 7sec into SRP Lecture One

T. Export mill files

If all looks good then:

Perform Cutting
Check Output to file
Start Cutting
Center of block as origin
Save the files with a smart naming. Add Radius and min length
- Roughing1_MyFile_BR3_L14
- Finishing1_MyFile_BR3_L14

Go to: 17min 33sec into SRP Lecture One

U. Save also the SRP-project (.SPJ)

Now time for "The Practial Part"

See below

Go to: 19min 37sec into SRP Lecture One

3. The Practical Part

Follow the Video Lectures:

MDX40A video Lecture One

MDX50 video Lecture Two

Two MDX-40A One MDX-50

Manual finishing

How to safely and precisely cut your parts out of the block after milling

Video on how to Remove your parts from the block

Well Done!

2. For professional CNC milling machines export STEP or IGES files

STL-file can also be used but NURBS (step, iges) is prefered

Alias (NURBS) STEP or IGES export: go Here
Rhino (NURBS) STEP or IGES export: go Here

Sahos Milling Machine from Rhino or Alias

C.
Contact the CNC mill operator for 5-axis Milling

Go to THIS PAGE.

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