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.
Remove Excess Material ........... 98 Pre-Finish All Surfaces ............ 102 Finish Near-Flat Surfaces ......106 Finish the Blend Fillet..............108
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.
Project 4: Mill a Mold Core | 97
The Search Factor se ng in ESPRIT lets you increase the analysis of the part geometry to improve the accuracy of the toolpath. In the Opera ons Manager. Hiding Operat ions When you program surfaces. ESPRIT calculates the part boundaries so the tool follows a more intelligent pa ern with fewer reposi oning moves. 98 | Get Started with ESPRIT 2009 . ESPRIT lets you hide the display of exis ng opera ons while you are working and then display them again later. you can right-click on any opera on and click Hide to hide the toolpath or click Show to display a hidden toolpath. the maximum amount of stock material must be quickly and evenly removed before the pre-ﬁnishing and ﬁnishing passes can begin. use a higher Search Factor value to allow for a more precise scanning of your part. Se ng Search Factor to 2 divides each grid in half (in eﬀect doubling the number of grids). The opera on searches for cu ng passes based on the original calculated grid. This makes it faster and easier to program your parts by displaying only the opera ons you are currently working on. Search Factor is applied to a part based on a grid calculated from the tool size. This can cause mul ple tool reposi oning moves and a tool mo on that does not follow the curves of the part. and so on. the tolerance. Variable-Z Roughing Typical surface roughing opera ons use a standard cu ng pa ern. trochoidal roughing brings beneﬁts to any type of machine by providing a more constant tool load and a be er surface ﬁnish.Remove Excess Material When complex surfaces are milled. Although developed for high-speed machining. For surfaces that require high precision machining. such as a back and forth mo on. The Variable-Z Roughing command creates an op mized roughing opera on with cu ng passes that adapt to the shape of the part. to remove material at speciﬁed incremental depths. and the step over speciﬁed on the opera on technology page. At each incremental depth of the opera on. The default value for Search Factor is 1. the complexity of the diﬀerent toolpaths can make it diﬃcult to see what you are doing on the screen. It is cri cal that the roughed part have a constant stock so the ﬁnishing tools can cut as eﬀec vely as possible. Search Factor Complex surfaces require complex toolpath. Trochoidal Tool Mot ion Trochoidal tool mo on lets you quickly rough parts at a constant material removal rate. se ng it to 3 divides each grid in thirds. Hidden opera ons simulate and post like visible opera ons.
click SolidMill FreeForm to display the toolbar. Create a Variable-Z Roughing Operat ion This opera on will use a Trochoid tool mo on pa ern. Project 4: Mill a Mold Core | 99 . When the spiral reaches the maximum radius that will ﬁt. 2. ESPRIT will create a spiral in the largest machinable area to maintain a constant level of tool loading. At each incremental depth of 2mm. On the Smart toolbar. The Search Factor for this opera on is set to 2.esp 3.Open t he Par t File 1. On the File menu. The trochoidal feedrate is set on the Advanced page.Surfaces\mold_core. 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 rest of the tool path uses an adjustable curve that adapts to the shape of the part. Locate and open the following ﬁle: Milling . click Open.
prc Step 4 Click OK Step 5 Select the solid model Step 6 Click Cycle Stop to create the opera on 100 | Get Started with ESPRIT 2009 .Surfaces\Technology\1-Variable-Z.Step 1 Click Variable-Z Roughing Step 2 Right-click inside the technology page and click Open Step 3 Open the ﬁle: Milling .
Step 7 Click the Opera ons tab Step 8 Right-click on the roughing opera on and click Hide Project 4: Mill a Mold Core | 101 .
Separate machining op ons are available for ver cal and horizontal cu ng passes. 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. leaving a stock allowance of 0. 102 | Get Started with ESPRIT 2009 . The entry and exit moves are both set to Tangent Radius. you have the op on to machine the en re part or you can selec vely machine ver cal or horizontal areas only. 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. When you machine the en re part. These distances are measured from the edge of the part along the entry or exit move. Op ons for machining ver cal areas are located on the Z-Level Finish technology page. Entry and exit moves are aﬀected by two feedrate se ngs: XY Feedrate and Entry Feedrate %.Pre-Finish All Surfaces The next step in this project is to pre-ﬁnish the surfaces. you can choose to cut the ver cal and horizontal areas with diﬀerent tools. 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. Accelerat ion / Decelerat ion Distance For high-speed machining.4mm. which will create a 10mm radiused move tangent to the toolpath. Create Finishing Passes on Near-Ver t ical A reas You will begin by pre-ﬁnishing all the near-ver cal areas of the part. When you create a Z-Level Finishing opera on. 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. Horizontal areas will not be cut. Feeds and speeds and entry/exit moves can be deﬁned independently for z-level 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. while op ons for machining horizontal areas are located on the Floor Finish page. The incremental depth for each z-level is 0.1mm.
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 Project 4: Mill a Mold Core | 103 .
When Cut Horizontal Areas is set to Only. This means that only areas with a slope angle less than or equal to 15 degrees will be cut. Step 1 Click Z-Level Finishing Step 2 Open the ﬁle: 3-Z-Level_Horizontal. the Cut Horizontal Areas is set to Only and the Max Slope Angle op on is set to 15 degrees. On the Floor Finish page. The same stock allowance of 0.Create Finishing Passes on Near-Horizont al A reas This opera on also uses Tangent Radius entry and exit moves except that the radius is now set to 3mm. the se ngs on the Z-Level Finish page are disabled.prc Step 3 Click OK 104 | Get Started with ESPRIT 2009 .4mm is used.
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 Project 4: Mill a Mold Core | 105 .
individual areas of that part can be deﬁned as ﬂat or steep based on the slope of the surface. separate opera ons can be created using diﬀerent milling strategies. ESPRIT calculates the distance of the step over between each cu ng pass. Morph moves use bridge movements between cu ng passes while Morph Spiral uses gradual spiral passes between cu ng passes. please no ce how the tool mo on adapts to the shape of each ﬂat area. In addi on to crea ng a ﬁnishing opera on for an en re part. When scallop height is speciﬁed. Once these areas are iden ﬁed. A er the toolpath is created. 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. With Morph In. you need to ﬁnish the ﬂat areas of the mold insert. the toolpath begins by following the shape of the outer proﬁle and then gradually adjusts to the shape of the inner proﬁle. 106 | Get Started with ESPRIT 2009 . These tool mo on pa erns are called Morph and Morph Spiral. the cu ng passes will be oﬀset from any wall by 0. There is no need to create addi onal toolpath boundaries. 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. To provide clearance.Finish Near-Flat Surfaces In order to provide a good ma ng surface with the other mold components. Morph Out produces the exact same toolpath except that the toolpath begins with the inner proﬁle. Morphing Tool Mot ion ESPRIT oﬀers tool mo on pa erns that automa cally adapt to the shape of an outer boundary and an inner boundary. 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. Cut Near-Flat A reas 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. These tool mo on pa erns typically require the selec on of outer and inner boundary features. Finishing oﬀers a wide variety of tool mo on pa erns that give you full control over how your toolpath is created.1mm.
prc Step 3 Click OK Step 4 Use the default surfaces Step 5 Click Cycle Stop Project 4: Mill a Mold Core | 107 .Step 1 Click Finishing Step 2 Open the ﬁle: 4-AreaFinish.
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.Step 6 Hide the ﬁnishing opera on Finish the Blend Fillet Next. except that this me you will use the Morph Spiral In pa ern to produce gradual spiraling passes. 108 | Get Started with ESPRIT 2009 . You will ﬁrst deﬁne the machining technology and then ESPRIT will prompt you to select ﬁrst the outer boundary and then the inner boundary. You will also need to select the outer and inner boundaries since you will not be using slope machining to calculate the boundaries.
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 Project 4: Mill a Mold Core | 109 .
Step 5 Select the chain feature for the inner boundary Step 6 Use the default surfaces and click Cycle Stop 110 | Get Started with ESPRIT 2009 .