5 Axis Cutting Using Delcam Powermill Written by: John Eberhart DM Lab Tutorial

Transcription

1 5 Axis Cutting Using Delcam Powermill Written by: John Eberhart DM Lab Tutorial This tutorial covers how to setup a job for a Multi-Axis Toolpath specifi cally using the Robot. Note: You need to follow the 3 Axis Tutorial First before starting this tutorial. This tutorial starts where the previous tutorial left off. We already have our tools loaded and we have created a rough Top cut created. Setting a new Workplane for a sideways cut The robot will always align its spindle axis along the Z axis and the tip of the spindle always points towards the origin. In powermill to rotate the spindle, you create a new reference plane and rotate the new reference plane so the Z axis and thus the robot arm will rotate to align with the new Z Axis position. Create a new Workplane Name your Workplane and set it as active Right Click on Workplanes and Select Create Workplane. The following Pop up window will appear. Model origin Activated Workplane in red.

2 Adjusting the Workplane using the pop up window. Using the pop up window, you can move the position and Rotation of the active workplane by inputting a value in millimeters and clicking on the appropriate translation or rotation button. Using the input Box, I rotated the Workplane so the Z axis, and thus the tool is pointing towards the back. I also have the workplane s X and Y axis so they are on the surface and to the back of the box. If these axes were in the middle the tool would start at the middle of your piece. Note: If the block is moving with the tool, then you forgot to lock down the block. To do this open the block settings and click the lock button. (See the 3 Axis tutorial on how to do this) Perform a Rough Cut on the back of the piece. Click on the machining strategies button, and using the same settings in the 3 Axis tutorial, I generated a rough cut on the back of the model. In addition, I limited the depth of the cut using the Limit Toolpath method. To limit the toolpath, right click on the toolpath, and select Edit>Limit Completed Toolpath Limited Toolpath. Note: remember to reset your safe Z heights before calculating the tool path.

3 Roughing the Front of the Piece: To rough the front of the model, we are going to create a new Workplane, then move and rotate the workplane so that the tool is pointing to the front of the model. Make sure none of the workplanes you already created are active. if they are, right click and uncheck activate. New Workplane (Rough Front) Active the new workplane Using the Move and Rotate Controls Position the new workplane to the front of the model, and make sure the tool is pointing towards the model. New Workplane position in Red Note: remember to reset your safe Z heights before calculating the tool path. Completed Toolpath Limited Toolpath.

4 Setting up Tool moves to control the Robot Arm from the Back to the Front: Robots by defi nitions are very stupid. Currently if we were to cut this job, the robot would fi nish the back, and then take the shortest path to the front of the model and start cutting the front. That means the robot s arm and spindle would move through the part destroying it in the process. If you simulate the toolpaths, there will be a hole in the middle of the model where the bit passed. Cut in model when bit moved from top to back Hole in model when bit passed through the model moving from the back to the front In order to control how the arm moves around your model, you need to create a series of workplanes and those workplanes are then placed in the correct move order in the NC program. Crate a new Workplane. Right click on Workplanes and right click and select Create Workplane. Position of New Workplane in highlighted Red I called this workplane Toolmove 1 and made it active. Using my Move and Rotate controls, I positioned the workplane to the top front and left side of the model. Note: DO NOT create a workplane from an existing workplane, AlWAYS deactive any workplanes fi rst. If you create a workplane from an existing workplane, the robot will not follow the connecting move correctly and could result in hitting your workpiece, the fl oor, or the table.

5 Repeat the process and Create another toolmove workplane for the front of the model Tool Move 1 Tool Move 2 Settings for tool move 2 reference plane Loading the tool Move reference Planes into the NC program: Activate the NC program by right clicking and select activate. Tool Move 2 Tool Move 1 Drag and drop the workplanes in to the NC program in the proper order. In the Powermill window you will see blue connection lines stitching the toolpaths and workplanes together. The Arrows indicate the direction of the connection moves. Simulate your job, verify that you have no collisions and post your Job!

6 5 Axis Finish Cuts Powermill Allows you to perform a number of different types of fi nish cuts. To perform a fi nish type cut, click on the toolpath strategies Icon and select a fi nish cut from the library of cuts. Click the Finishing tab for the fi nishing library Select a Finishing Strategy and a preview of how the cut will work appears Most of the Toolpath Strategies are for very specifi c uses. You should spend some time going through the various types of fi nish strategies. Raster Finishing is most like the fi nishing strategy in Madcam or Surfacm. Corner Pencil Finishing is the same as the Pencil cut in madcam. Applying a 5 Axis Finish Cut. Activate the front rough Workplane and click on the toolpath strategies button. Note: remember to reset your safe Z heights before calculating the tool path.

7 The Raster Finishing settings window appears. Choose the bit you want to use. In this case I am using a 1/2 dia ball nosed bit. Leave our tolerance at 0.1 Your offset thickness should be at 0.0 Stepover will be determined by the fi nish quality. Smaller the stepover, the smoother the fi nish, but it takes longer. Name your toolpath (Finish planar) Choose a starting corner. You can adjust the ordering of the passes. If you are cutting wood, you want to choose one way. If you are cutting foam, both ways is fi ne. I recommend you do a stepover of 1-3mm This sets the lead in and lead out controls we will get into this in more detail. Leave tool axis on vertical for now, we will get into this as well. Clicking draw and preview will show a rough idea of how the toolpath will look. Previewed Toolpath Hit Apply to calculate the toolpath

8 The planer cut is shown. Green lines are actual cutting moves, blue and red lines are lead in and lead outs. This particular toolpath has a lot of wasted moves. We can correct this by adjusting the Lead in and lead out moves. To do this right click on the fi nish planar toolpath, and choose settings In powermill, you can pull up a completed toolpath settings window and recycle the job, allowing you to adjust the settings and recalculate the job. Click on the recycle button to reactivate the toolpath settings. Click on the Leads and Links setting button. The above pop up window will appear. Click on the links tab. Under the Short, options, choose Skim. For the Long and default choose Skim. This will make the bit follow along the surface when it is moving from one cutting line to another. Click the Apply links Button and then accept. Click Accept again to recalculate the toolpath.

9 Resulting revised Links. Projected Point Full 5 Axis Finishing: Click on Toolpath Strategies, then select Projection Plane Finishing Note: remember to reset your safe Z heights before calculating the tool path.

10 Set your tool Set your Stepover Anchor point sets the beginning of the plane Azimuth and Elevations sets the 3D orientation of the plane. Move the sliders and watch the plane rotate Direction sets the direction of the projection. You want the direction arrows on the plane to point toward the model. Set your Lead in and Lead outs to Skim and on Surface Pattern direction sets either horizontal or vertical passes Height and Width sets the size of the projected plane. Click on draw and Preview Previewed model. The plane with the horizontal lines is the projected plane. The stepover sets the density of the horizontal lines. Click Apply to calculate the projected plane. This toolpath is fi ne, but the bit will always stay vertical off of the piece. With a 5 Axis mill you can tip the bit back and forth to allow you to get into tight areas. To do this recycle the Projected Plane Toolpath.

11 With the toolpath recycled, click on the Tool Axis Icon. At the pop up window. Choose Toward Point. This will point the axis of the tool toward a single point. That point is specifi ed by XY and Z coordinates. If you view your model in a orthogonal view, you can get a reading on the XY and Z coordinates. Check Draw tool Axis and Auto Collision Avoidance Then Click the Collision Avoidance Tab. You can specify Special tool axis tilts in this drop down You can set a clearance distance from your shank and Holder Click Accept when done and recalculate your toolpath.

12 The tool is leaning as the Bit Cuts the surface.