3D Drilling Lab

1.1. Summary

1.2. Starting the 3D machining wizard

1.3. Define Machining Process data

1.4. Defining Drill bit

1.4.1. Drill bit object definition

1.4.2. Defining drill bit geometry

1.4.3. Assigning the tool material

1.4.4. Generating mesh for Tool

1.4.5. Defining BCC for Tool

1.5. Defining Workpiece

1.5.1. Workpiece object definition

1.5.2. Defining geometry for Workpiece

1.5.3. Defining Workpiece material

1.5.4. Workpiece Mesh Generation

1.5.5. Defining BCC for Workpiece

1.6. Positioning the objects

1.7. Defining tool wear parameters

1.8. Defining inter-object relations

1.9. Defining step controls

1.10. Generating database

1.11.Running Simulation

1.12. Post Processing simulation results

Summary

In this lab, we will demonstrate how to setup drilling lab using 3D Cutting wizard. Drilling simulations in DEFORM are time consuming due to the number of revolutions of a drill necessary to establish characteristic behaviour. Therefore, every effort will be made to optimize problem size. Considerations include keeping the workpiece as small as possible while capturing geometry (both in diameter and thickness), using the largest element which can adequately capture chip geometry, and possibly pre-shaping the workpiece to eliminate the necessity to simulate the transient point penetration before the drill reaches full depth. This tutorial will use the example of a 6mm two flute twist drill running at 400RPM with a 0.15mm/rev feed.

Starting the 3D machining wizard

Create a new problem either by selecting File **New Problem** or by clicking the New Problem icon. The Problem Setup window will appear as shown in Fig. 3DDL1.1.) Select “ 3D Cutting “ radio button and Unit system as “SI “ (See Fig. 3DDL1.1.). Define Problem Name as “3D_drilling “ and click on button to open a new Problem with 3D Cutting operation in MO wizard.

Creating new Machining operation

Define Machining Process data

In the ‘Process’ page, select Cutting type as ‘Drilling ‘, enter the Environment temperature as 20 °C and use default Convection coefficient as 0.02 N/sec/mm/C. Define Rotational speed as 400 rpm and feed rate (f) as 0.15 mm/rev as shown in the Fig. 3DDL1.2. Click until Tool page.

Setting up process parameters for Drilling operation

Defining Drill bit

Drill bit object definition

In this Tool page, Define the temperature as 20 °C and turn on the “Calculatetool temperature ” check box so that we can mesh the tool to calculate temperature distribution as shown in the Fig. 3DDL1.3. Click to Tool geometry page.

Tool object page

Defining drill bit geometry

In this Insert Geometry page, the user needs to define the tool geometry using the Define primitive link. Using the link as shown in the Fig. 3DDL1.4., we will be opening ‘Drillbit Primitive’ window as shown in the Fig. 3DDL1.5. click on button to create drill bit geometry using the parameters as shown in the Fig. 3DDL1.5.

Tool geometry page

Defining drill bit geometry

Assigning the tool material

In Material Window, we need to load the material from the library. So, click on “Load form Library” option and select hot formingdie material category and select ‘Carbide(15%Cobalt) ‘ material from the list to assign the material for tool as shown in the Fig. 3DDL1.6. Click to generate mesh for tool.

Assigning the Tool Material

Generating mesh for Tool

In Tool mesh page, select the UseRelative mesh size method. Define target number of elements as 20000 and size ratio as 0.3 as shown in the Fig. 3DDL1.7. Click on to generate mesh. Mesh looks like as shown in Fig. 3DDL1.7. Click to BCC page.

Tool Mesh Generation using relative mesh size

Defining BCC for Tool

In this BCC Page, the user can define Thermal BCCs “HeatExchange withEnvironment ” and “Temperature ”. The default BCC is assigned to the entre outer surface of the drill bit automatically after generating the mesh as shown in the Fig. 3DDL1.8.

Heat exchange BCC over Tool

Defining Workpiece

Workpiece object definition

In this Workpiece object page, define the temperature as 20 °C and object type as plastic as shown in the Fig. 3DDL1.9. Click to workpiece geometry page.

Workpiece object Page

Defining geometry for Workpiece

In this Workpiece Geometry page, we need to define the workpiece geometry using the . In workpiece geometry primitive page, select the cylinder radio button and defineDiameter(D) as 12mm , Thickness as 4mm and Drilltip depth as 3.15mm as shown in the Fig. 3DDL1.10.

Creating the cylinder workpiece geometry

Defining Workpiece material

In Material Window, we need to load the material from the library. So, click on “LoadformLibrary ” option and select AISI-1045(Machining) from the Steel category to assign the material for workpiece as shown in the Fig. 3DDL1.11. Click to generate mesh for workpiece.

Assigning the material for the workpiece

Workpiece Mesh Generation

After the work piece geometry is generated, in mesh page, using the absolute mesh size method define element size ratio as 10 , and Minimum element size as 0.04 mm as shown in Fig. 3DDL1.12. Click on to complete mesh generation for the Workpiece.

Runtime meshing parameters:

To set runtime meshing parameters, switch to expert mode using . In expert mode selectweighting factors tab and define Strain weight to about 0.65 , StrainRate weight to about 0.35 and make other weights to zero (Including mesh windows) as runtime mesh parameters (See the Fig. 3DDL1.13.). After setting weighing factors, switch to guided mode using . Click to BCC page.

Workpiece mesh generation using absolute mesh size

Runtime Workpiece mesh generation weighting factor parameters

Defining BCC for Workpiece

In BCC Page, by default the velocity of all nodes on the circumference of the workpiece are fixed in X, Y and Z directions as shown in the Fig. 3DDL1.14. Heat exchange boundary conditions are assigned to top and bottom surfaces automatically during mesh generation as shown in the Fig. 3DDL1.15. Click to Control page.

Defining the velocity BCC data

Defining Heat Exchange BCC

Positioning the objects

In Control page, click on ‘Position objects’ and check the position of Tool. If the Tool is not in contact with Workpiece, position the tool using interference method and click to define tool wear parameters.

Defining tool wear parameters

In Tool wear page, turn on the “Definemodel to calculate tool wea r” check box and select Usui model, use the default parameters for Usui model as shown in the Fig. 3DDL1.16. Click to Contact page.

Defining Tool Wear parameters

Defining inter-object relations

In Contact page, we will use default relations. Click on Tool - Workpiece relation Edit button and define shear friction factor as 0.6 and the interface heat transfer coefficient as 40 N/sec/mm/C (as shown in Fig. 3DDL1.17.), click on to generate contacts. Click to Step Control page.

Contact page

Defining step controls

In Step control page, define the drill depth as 3.5mm and select User radio button to set user definedtime step increment as 0.0005 , keep the rest of the values to default as shown in the Fig. 3DDL1.18. and proceed to generate the database by clicking .

Step controls page in GUIDED Mode

Generating database

In Generate database page, click on the button to generate the database. Observe messages in Message tab informing database generation status. If there are any errors, we need to correct them before generating Database

Running Simulation

Once the database has been generated switch to the Simulation mode by clicking on button above the operation tree. Click on the action label to open the Run Options dialog as shown in Fig. 3DDL1.19. Use the default ContinueRun option to select “Continue from the last step ” (from step -1) option and then select the Simulation mode as Interactive radio button. Click on button to run the simulation.

To define MPI settings, click on button, Run Options window will expand and displays options to define MPI settings for simulation (max number of processors that can be defined depend on your 3D MPI license).

Run Simulation Window

Monitor the progress of the simulation by looking at the Simulation Message and Simulation Log tab, making sure that option is checked. User can view the drilling process as the simulation proceeds to the specified drill depth from Simulation graphics.

Post Processing simulation results

When the simulation is completed, review the results by switching to Post mode using the button above the Simulation tool bar. Play through the steps of the simulation and observe the chip formation during drilling process.