1. CAM与自动编程
封志明

2. --Chapter VII-- VII、Face Milling Z-Level Milling overview
Z-Level Milling geometry
Z-Level Milling Operation Parameters
Z-Level Milling Cutting Parameters
Z-level Milling Example
Mechanical University

3. To be able to Create a ZLevel Milling.
Chapter VII
To understand the Z-Level milling.
To understand Steep Containment.
Objectives
To be able to Create a ZLevel Milling.

4. 7.1 Z-Level Milling Overview
7.1.1 What’s Z-Level milling
Use Z-Level Milling for fixed- axis semi-finishing and finishing. Z-Level Milling maintains a near constant scallop height and chip load on steep walls and can be especially effective for high speed machining.
Z-Level Milling

5. 7.1 Z-Level Milling Overview
With Z-Level Milling, you can do the following:
Profile the entire part, or specify Steep Containment so that only areas with a steepness greater than the specified angle are profiled.
Cut multiple levels in one operation.
Cut multiple features (regions) in one operation.
Cut by level for thin-walled parts.
Maintain the tool in constant contact with the material.

6. 7.1 Z-Level Milling Overview
7.1.2 Advantage to use Z-Level milling
Z-Level Milling has the following advantages for semi-finishing and finishing:
Advantages
Zlevel does not require blank geometry.
Zlevel has steep containment.
When cutting depth first, Zlevel orders by shape, where Cavity Milling orders by region.
On closed shapes, Zlevel can move from level to level by ramping directly on the part, to create a helical-like path.
On open shapes, Zlevel can cut in alternating directions, creating a zig-zag motion down a wall.

7. 7.1 Z-Level Milling Overview
7.1.3 Z-Level Milling operation Subtypes
Tab.7-1 Z-Level Milling operation subtypes

8. 7.2 Z-Level Milling Geometry
Tab.7-2 Valid geometry for Z-Level Milling

9. 7.3 Z-Level Milling Operation Parameters
Steep Angle
The steepness of the part at any given point is defined by the angle between the tool axis and the normal of the face. When specifying Steep Containment, only areas with a steepness greater than the specified angle are profiled.
Option
Description
Steep Containment
Restricting the cut area based on the steepness of the part
Merge Distance
Connecting the end points of cutting moves that are less than the specified distance apart to eliminate unwanted tool retracts .
Minimum Cut Length
Eliminating tool path segments shorter than the specified value.

10. 7.4 Z-Level Milling Cutting Parameters
7.4.2 Between Levels
Between Levels is available for Z-level Milling only. It allows users to cut all levels without lifting back up to the clearance plane.
Use Transfer Method
Direct on Part
Ramp on Part
Stagger Ramp on Part

11. 7.4 Z-Level Milling Cutting Parameters
7.4.3 Cut Between Levels
Cut Between Levels option is used to create extra cuts when there is a gap between the cut levels in Z-level machining, which eliminates the large scallops in shallow regions left from standard level-to-level machining and eliminates the need to create a separate area milling operation for non-steep areas, or to use a very small depth of cut to control scallops in non-steep areas. It can minimizes excessive tool wear or even breakage from rapidly loading and unloading the tool in areas that have large scallops left behind from previous operations, producing a more uniform stock for semi-finishing and a more consistent surface finish with fewer retracts and engages for finishing.

12. 7.4 Z-Level Milling Cutting Parameters
7.4.3 Cut Between Levels
Cut Between Levels off
Cut Between Levels on
Notice the shallow regions have large gaps
Notice it produces a more uniform cut path and eliminates large gaps between cut levels.

13. 7.4 Z-Level Milling Cutting Parameters
Reference Tool 
Reference Tool is used to eliminate tool motion where there is no material. It references a larger tool from a previous operation. The smaller tool in the current operation removes the remaining material in the uncut regions where the larger reference tool could not fit.
Overlap Distance: Extends the width of the area to machine for the specified distance along the tangent surfaces of the remaining material.
(a) Overlap Distance set to zero (b) Overlap Distance set to a value of 15.00

14. 7.5 Z-Level Milling Example
Z-Level Milling Part Model
Tool Path of Z-level Milling with Direct on Part Option
Tool Path of Z-level Milling with User Defined Cutting Levels

15. THANKS
封志明/机械工程学院
2019年5月19日