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- Technical Information
- [FA Mechanical Parts] CNC Turning
- Design Guidelines
- Difference in Shapes Between the 3D Model and the Finished Product
Difference in Shapes Between the 3D Model and the Finished Product
Although 3D CAD data will be used for manufacturing, the following cases may result in differences between the 3D model and the finished product.
- Points to Note on the Finished Shape of Internal and External Corners of Turning parts
- Points to Note on Center Holes
- Points to Note on the Bottom of Holes (Machined and Cut)
- Points to note regarding cylinder corners
- Points to Note on Incomplete Threads
- Points to note for the finished shape of the end-face groove inner corners
- Points to Note for the Finished Shape of Pocket Internal Corners
- Points to Note for Sliting processing
- Hexagonal Hole Notes
Points to Note on the Finished Shape of Internal and External Corners of Turning parts
Please check the examples and notes for differences in the finished product.
Tip
The finish conditions are as follows.- Models with external edges of less than C/R0.5 will have C/R 0.1 to 0.4 mm or slight chamfer.
- If the internal corners of the cylinder are less than 0.5 and there is no relief groove in the model, the tool edge will leave a corner of R0-R0.4mm.
→Click here to specify “Corner R0” without modeling a relief groove.
Caution
- When modelled with ≥C0.5 mm or more, machining will be in accordance with the 3D data.
- When modelled with ≥R0.5 mm or more, machining will be in accordance with the 3D data.
Caution
Specification of “no chamfer” is not supported.Notes
-
- A standard retaining ring grooving tool has corner R0.2
- For retaining ring standards, click here.＞＞＞Specifications for External Thread and Internal Thread, Keyways, Holes and Pockets
Outer diameter grooving
Inner diameter grooving
Points to Note on Center Holes
The center hole made in the end face is used to keep the workpiece in place and to prevent core deviation when rotating the product.
Caution
- 「”Center hole cannot be left” can be selected, but there may be restrictions on the shapes that can be machined that make the option unavailable. When this occurs, check the “Precaution” in the upper-left corner of the 3D Viewer.
Notes
(1) If you select “Remove center hole”, an arrow will point to the part.
(2) If the component has an inner diameter, no arrow will point to the part.
Points to Note on the Bottom of Holes (Machined and Cut)
A drill tip shape remains at the bottom of the hole (machined and cut).
| Shape patterns | Inner diameter hole does not have a step | Inner diameter hole has a step |
|---|---|---|
| A |  |
 |
| Drill tip shape remains (flat bottom will be 1mm or more) | ||
| B |  |
 |
| Drill tip shape remains, no flat bottom | ||
- The type of the bottom of the hole will depend on the diameter and depth of the hole.
- Example: If the inner diameter (D) is 10mm and the hole depth is 35mm, the depth of 35mm ÷ inner diameter of 10mm = 3.5D, so the bottom of the hole type will be B.
| Inner diameter(D) | the hole depth | ||
|---|---|---|---|
| to 3D | 3D to 5D | 5D to 10D | |
| D≦⌀6 | B | B | B |
| ⌀6 ＜D≦⌀30 | A | B | B |
| ⌀30＜D | A | A | A |
If a flat bottom hole is required, please request it in “Additional Information”. We will confirm whether or not we can accommodate your request and reply.
Points to note regarding cylinder corners
Please check the examples and notes for differences in the finished product.
Outer diameter
①When “Corner R0 specification” is specified in the dialog
- When you want to minimize the corner R or specify the relief groove
- → Select “Corner R0”
Tip
- Corner R0 has a width of less than corner R0.2 to R0.4, so the depth may be less than 0.5mm. You cannot choose.
- ① When machining with R0.4 tools
- ②When machining with R0.2 tools with R0.4 tools
Notes
In the following cases, “Corner R0” does not apply.
| (1) The model has corner R0.5 or greater | (2) The model has a relief groove |
 |
 |
②If you specify “Corner R0 to R0.4 or less” in the dialog
- When the cylindrical corner can be any shape
- → Select “Corner Radius between R0 to R0.4”.
Tip
- Arbitrary R shape of cylindrical corner
- ① Machining R remains
- ② Relief groove (1) Minimum clearance only at the cylindrical corner
-
Finished shape after
Detailed figure
- ③ Relief groove (2) Relief shape on cylindrical part + flange part
-
Finished shape after machining
Detailed figure
③When modeling “corner R0.5 or more”
If the corners are modeled with R0.5 or higher, the shape will be as shown below.
Modeling of R0.5 or higher in corners- Finished shape after machining
- Detailed figure
Inner diameter
Any relief groove below may be set.
Cross section
①Detailed figure
②Detailed figure
Notes
At the bottom left of the 3Dviewer, you can see the handling information for the cylindrical corners.
Points to Note on Incomplete Threads
The required undercut shape (length and depth) to ensure the threaded portion length for an incomplete threaded position is shown. See the example below.
[mm]
| External Thread | Internal Thread | ||
|---|---|---|---|
| Modelling | Without undercut |  |
 |
| With undercut |  |
 |
|
| (1) Lower limit for the length of the incomplete thread and the width of the undercut. | Pitch × 2.0 | Pitch × 2.5 + 2 | |
| (2) Lower limit of the length of the threaded (external thread) and the depth of the threaded (internal thread). | Pitch × 2.0 | Pitch × 2.0 | |
| (3) Chamfered edge | Chamfered to prevent burr | Chamfered to prevent burr | |
| (4) Minimum undercut depth value | Pitch × 0.75 | Pitch × 0.75 | |
Caution
Parts with “Pitch × 0.75” or less set to the minimum value for the undercut depth(4) can be machined, but thread marks may occur.
Reference model
Actual finished shape after machining
Tip
- The [Notes] shown in the red box below describe the applicable thread length/thread depth.
| Example 1) Outer diameter specification: male thread thread length 27.5mm – 1.5 (pitch) x 2.0 = 24.5mm | Example 2) Inner diameter specification: female screw thread depth 30mm – (1.0(pitch) × 2.5 + 2.0) ＝ 25.5mm |
 |
 |
Caution
- The thread shape cannot be identified. Set the outer and inner threads.
Points to note for the finished shape of the end-face groove inner corners
Check the examples and notes for differences from the final product.
Model with sharp edges in end face groove
Actual finished shape after machining
"*Finished with a radius (R) ranging from 0.1 to 0.5 mm.
"
Notes
Since the shape is finished to R0.1 to 0.5, no modelling is required. Design with sharp edges.Points to Note for the Finished Shape of Pocket Internal Corners
Check the examples and notes for differences from the final product.
Notch (pocket)
Shape of less than R0.5 including sharp edges
Actual finished shape after machining
"*Finished with a radius (R) ranging from 0.1 to 0.5 mm.
"
Caution
- The machined curve on the sides of the pocket depends on the tool diameter, which is chosen as small as possible.
- If there are any discrepancies between the model and the finished form, please feel free to let us know.
Points to Note for Sliting processing
The dimensions of the parts may change as a result of the slitting process. Therefore, the dimensions of the following shapes are guaranteed based on the measurements taken before slitting.
Hexagonal Hole Notes
Information and examples of differences between the model and the finished part.
- The shape of the finished hexagonal hole will vary depending on the distance across the flats.
- The modeled depth is used as a reference, and the shape of the bottom of the hole will vary.
Hexagonal Hole corresponding shapes and sizes
| Distance across the flats | Metal | Resin |
|---|---|---|
| 2 | Finished Shape① | Finished Shape② |
| 2.5 | ||
| 3 | ||
| 4 | ||
| 5 | ||
| 6 | ||
| 8 |
Caution
The roughness specified for the surface does not apply to the internal hexagon.
Finished Shape①
| Distance across the flats | Metal | Resin |
|---|---|---|
| Other | Finished Shape② | |
Notes
The tolerance for the distance across the flats meets to the JIS B 1176.
Finished Shape②
