esprit milling tutorial 03

Project 4: Mill a Mold Core | 97

PRO

JECT

Mill a Mold Core

The mold insert in this project is part of a mold assembly

used to manufacture a 2-bu�on computer mouse. This

part will give you a good overview of surface roughing

and finishing techniques in ESPRIT. Not all surfaces of this

sample part will be machined completely.

The intent of this project is to teach you the process for

milling complex surfaces. By the end of this lesson you will

know how to use the more advanced milling techniques

offered by ESPRIT that let you op#mize your toolpaths and

cut your parts the way you want to.

4

The files for this project are available for download from

ESPRITWeb » File Library » ESPRIT 2009 and from the ESPRIT

CD.

All dimensions in this tutorial are in millimeters. Make sure

System Unit on the Tools menu is set to Metric.

Before you start this lesson, you can review and simulate the

cu$ng opera#ons in the following file:

Milling - Surfaces\mold_core_complete.esp.

Remove Excess Material ........... 98

Pre-Finish All Surfaces ............ 102

Finish Near-Flat Surfaces ...... 106

Finish the Blend Fillet.............. 108

98 | Get Started with ESPRIT 2009

Remove Excess MaterialWhen complex surfaces are milled, the maximum amount of stock material must be quickly

and evenly removed before the pre-finishing and finishing passes can begin. It is cri#cal that the

roughed part have a constant stock so the finishing tools can cut as effec#vely as possible.

Variable-Z Roughing

Typical surface roughing opera#ons use a standard cu$ng pa�ern, such as a back and forth

mo#on, to remove material at specified incremental depths. This can cause mul#ple tool

reposi#oning moves and a tool mo#on that does not follow the curves of the part.

The Variable-Z Roughing command creates an op#mized roughing opera#on with cu$ng passes

that adapt to the shape of the part. At each incremental depth of the opera#on, ESPRIT calculates

the part boundaries so the tool follows a more intelligent pa�ern with fewer reposi#oning moves.

Trochoidal Tool Motion

Trochoidal tool mo#on lets you quickly rough parts at a constant material removal rate. Although

developed for high-speed machining, trochoidal roughing brings benefits to any type of machine

by providing a more constant tool load and a be�er surface finish.

Search Factor

Complex surfaces require complex toolpath. The Search Factor se$ng in ESPRIT lets you increase

the analysis of the part geometry to improve the accuracy of the toolpath.

Search Factor is applied to a part based on a grid calculated from the tool size, the tolerance, and

the step over specified on the opera#on technology page. The default value for Search Factor is

1. The opera#on searches for cu$ng passes based on the original calculated grid. Se$ng Search

Factor to 2 divides each grid in half (in effect doubling the number of grids), se$ng it to 3 divides

each grid in thirds, and so on.

For surfaces that require high precision machining, use a higher Search Factor value to allow for a

more precise scanning of your part.

Hiding Operations

When you program surfaces, the complexity of the different toolpaths can make it difficult to see

what you are doing on the screen. ESPRIT lets you hide the display of exis#ng opera#ons while

you are working and then display them again later. This makes it faster and easier to program your

parts by displaying only the opera#ons you are currently working on.

In the Opera#ons Manager, you can right-click on any opera#on and click Hide to hide the toolpath

or click Show to display a hidden toolpath. Hidden opera#ons simulate and post like visible

opera#ons.


Open the Part File

On the 1. File menu, click Open.

Locate and open the following file: Milling - Surfaces\2. mold_core.esp

On the 3. Smart toolbar, click SolidMill FreeForm to display the toolbar.

Create a Variable-Z Roughing Operation

This opera#on will use a Trochoid tool mo#on pa�ern. At each incremental depth of 2mm,

ESPRIT will create a spiral in the largest machinable area to maintain a constant level of tool

loading. When the spiral reaches the maximum radius that will fit, the rest of the tool path uses

an adjustable curve that adapts to the shape of the part. The Search Factor for this opera#on is

set to 2.

The feedrate for the trochoidal cu$ng movement is about one and a half #mes faster than the

feedrate used for the entry and exit moves. The feedrate for non-trochoidal moves is set on the

General technology page. The trochoidal feedrate is set on the Advanced page.


Step 1

Click Variable-Z

Roughing

Step 3

Open the file:

Milling - Surfaces\Technology\1-Variable-Z.prc

Step 4

Click OK

Step 5

Select the solid modelStep 6

Click Cycle Stop to create the

opera#on

Step 2

Right-click inside the

technology page and

click Open


Step 7

Click the Opera#ons tab

Step 8

Right-click on the roughing

opera#on and click Hide


Pre-Finish All SurfacesThe next step in this project is to pre-finish the surfaces. You will do this by crea#ng two

opera#ons: one to pre-finish all the near-ver#cal areas and one to pre-finish all the near-horizontal

areas.

Z-Level Finishing

The Z-Level Finishing command combines two types of machining strategies into a single opera#on

for the best possible surface finish on complex surfaces. Separate machining op#ons are available

for ver#cal and horizontal cu$ng passes. The appropriate machining strategy is selected based

on a user-defined slope angle that indicates whether a surface should be considered ver#cal or

horizontal.

When you create a Z-Level Finishing opera#on, you have the op#on to machine the en#re part or

you can selec#vely machine ver#cal or horizontal areas only. When you machine the en#re part,

you can choose to cut the ver#cal and horizontal areas with different tools. Op#ons for machining

ver#cal areas are located on the Z-Level Finish technology page, while op#ons for machining

horizontal areas are located on the Floor Finish page. Feeds and speeds and entry/exit moves can

be defined independently for z-level and horizontal cu$ng passes.

Acceleration/Deceleration Distance

For high-speed machining, the Accelera#on Distance and Decelera#on Distance se$ngs ensure

that the machine is at the specified feedrate when the tool reaches the part and starts cu$ng

material.

Entry and exit moves are affected by two feedrate se$ngs: XY Feedrate and Entry Feedrate %.

Accelera#on Distance and Decelera#on Distance give you be�er control over how these feedrates

are applied over the en#re length of the entry and exit movement so that the tool can be cu$ng at

the full XY feedrate before it reaches the part.

These distances are measured from the edge of the part along the entry or exit move.

Create Finishing Passes on Near-Vert ical Areas

You will begin by pre-finishing all the near-ver#cal areas of the part, leaving a stock allowance

of 0.4mm. The entry and exit moves are both set to Tangent Radius, which will create a 10mm

radiused move tangent to the toolpath. The incremental depth for each z-level is 0.1mm.

Horizontal areas will not be cut.


Step 1

Click Z-Level Finishing

Step 2

Open the file:

2-Z-Level_Ver#cal.prc

Step 3

Click OK

Step 4

Answer Yes when prompted

to use the previously selected

surfaces

Step 5

Click Cycle Stop


Step 1

Click Z-Level Finishing

Step 2

Open the file:

3-Z-Level_Horizontal.prc

Step 3

Click OK

Create Finishing Passes on Near-Horizontal Areas

This opera#on also uses Tangent Radius entry and exit moves except that the radius is now set to

3mm. The same stock allowance of 0.4mm is used. On the Floor Finish page, the Cut Horizontal

Areas is set to Only and the Max Slope Angle op#on is set to 15 degrees. This means that only

areas with a slope angle less than or equal to 15 degrees will be cut. When Cut Horizontal Areas

is set to Only, the se$ngs on the Z-Level Finish page are disabled.


Step 4

Answer Yes when

prompted to use the

default surfaces

Step 5

Click Cycle Stop

Step 6

Hide the display of the

two Z-Level Finishing

opera#ons


Finish Near-Flat SurfacesIn order to provide a good ma#ng surface with the other mold components, you need to finish the

flat areas of the mold insert.

Finishing

The SolidMill Finishing command creates finishing passes using either a specified step over distance

or an allowable scallop height from the tool you are using. When scallop height is specified, ESPRIT

calculates the distance of the step over between each cu$ng pass. Finishing offers a wide variety

of tool mo#on pa�erns that give you full control over how your toolpath is created.

Morphing Tool Motion

ESPRIT offers tool mo#on pa�erns that automa#cally adapt to the shape of an outer boundary and

an inner boundary. These tool mo#on pa�erns are called Morph and Morph Spiral. Morph moves

use bridge movements between cu$ng passes while Morph Spiral uses gradual spiral passes

between cu$ng passes.

These tool mo#on pa�erns typically require the selec#on of outer and inner boundary features.

With Morph In, the toolpath begins by following the shape of the outer profile and then gradually

adjusts to the shape of the inner profile. Morph Out produces the exact same toolpath except that

the toolpath begins with the inner profile.

Slope Machining

Several op#ons are available that let you op#mize the machining of localized areas within a part

based on a user-defined slope angle. There is no need to create addi#onal toolpath boundaries.

In addi#on to crea#ng a finishing opera#on for an en#re part, individual areas of that part can be

defined as flat or steep based on the slope of the surface. Once these areas are iden#fied, separate

opera#ons can be created using different milling strategies.

Cut Near-Flat Areas

This opera#on will use the Morph Out tool mo#on pa�ern to cut all flat areas with a slope of less

than 10 degrees. To provide clearance, the cu$ng passes will be offset from any wall by 0.1mm.

There is no need to select inner and outer boundaries for the morph movement because ESPRIT

will automa#cally calculate the local boundaries around each flat area.

A*er the toolpath is created, please no#ce how the tool mo#on adapts to the shape of each flat

area.


Step 1

Click Finishing

Step 2

Open the file:

4-AreaFinish.prc

Step 3

Click OK

Step 4

Use the default

surfaces

Step 5

Click Cycle Stop


Step 6

Hide the finishing

opera#on

Finish the Blend FilletNext, you will create an opera#on to produce a smooth finish on the fillet around the mouse core.

This finishing opera#on will also use a morphing tool mo#on, except that this #me you will use the

Morph Spiral In pa�ern to produce gradual spiraling passes. You will also need to select the outer

and inner boundaries since you will not be using slope machining to calculate the boundaries.

You will first define the machining technology and then ESPRIT will prompt you to select first the

outer boundary and then the inner boundary.


Step 1

Click Finishing

Step 2

Open the file:

5-FilletFinish.prc

Step 3

Click OK

Step 4

Select the chain feature for

the outer boundary


Step 6

Use the default surfaces and

click Cycle Stop

Step 5

Select the chain feature for the

inner boundary

esprit milling tutorial 03

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