AutoCad 2007

[D-man]

Hey guys im trying to master AutoCAd a little more.

I have one major problem, when im saving the file the plasma does not like it what so ever! god know why!

Also is there a way to get the torch to start in the center of of a cut out?

regards

[Web Goblin]

What cnc control are you using? Have you assigned the lead-ins, lead-outs, inner and outer contours to different layers in autocad?
Normally if you wanted the cut to start in a specific position then thats where you would start your lead-in from.

[D-man]

This is the file... maybe you can see whats wrong with it?

[D-man]

To be honest im not sure. the machine is a blue marlin from techserve so its the techserve software which has a DXF to Gcode plugin

[D-man]

its would be ideal if i could draw the part in corel (wizz my way round that) and export to another program to create the proper dxf.... is there anything that can do this?

[Web Goblin]

I think it is because you have used polylines and splines to create the parts of the drawing. I havent met a conversion program yet thet will handle them correctly for profiling. If you draw all of your parts as lines, arcs, and circles you cant go wrong.
Try this test program to see if it works for you.
The drawing is made using my layer template which I use for all of my cad drawings. It consists of all the seperate layers I need to make a valid drawing for my post processor. If you want to keep this layer template simply erase the drawing and then save the empty drawing as a layer template. Then when you want to make another drawing simply start from loading the layer template and draw everything using it, then simply rename the file when you are saving it so that you dont overwrite the template file.

Measuring stand clamp test v1.dxf

[Ger21]

I think it is because you have used polylines and splines to create the parts of the drawing. I havent met a conversion program yet thet will handle them correctly for profiling.

Splines = BAD
Polylines = Good

I use polylines exclusively and Vectric's software works 100% of the time with my drawings.

Say you have a rectangular shape, and you want to start in the middle of the edge.
Here's what I do.

First, draw the rectangle. This will be used as a base for the final part.
Using the polyline tool, use a Midpoint or Nearest snap at the point you want to start. Then, click on the endpoints in the order (direction) you want the tool to go (Use running OSNAPS with Endpoint turned on). After clicking the last endpoint, hit "Enter" to exit the command. Now, delete the original rectangle, which should be visible in the open section of the new , open, rectangle. Then, select the new one, right click and choose polyline edit, and choose close.
Save as .v12 dxf and you should be good to go.

I actually use a macro that I wrote which exports g-code from within AutoCAD.

[Robin Hewitt]

I actually use a macro that I wrote which exports g-code from within AutoCAD.

Well done, most impressed. I baulked at working from within AutoCAD and took a different tack. I read a .dxf file and a .txt file that defines the missing parameters. I drive the mill directly, no G-code at all.

I looked at polylines, figured out how one magic number could define an arc but never wrote the interpreter. I just explode them before I export.

I found the trickiest bit was where the tool was too big to fit in all the little nooks and crannies, meaning I had to discard lots of entities. I did it, nearly, but should a pocket have a constriction below tool diameter I only get half of it. I found picking up on a sub-pocket surprisingly tricky, too easy to get phantoms. Remembering that a subsequent tool might have to do waste removal only on the uncut section was beyond me.

[Ger21]

Perhaps that is why you had problems stitching lines and arcs

With polylines, there was no need to attempt it, so no problems.

[Robin Hewitt]

Your part is easy to draw with AutoCAD.

Here it is step by step.

First set your snap to something useful like 1mm. Type SNAP spacebar 1 spacebar
You are now working to a grid so everything is neat and tidy.

Useful Function keys are F8 which toggles Ortho and F9 which toggles SNAP

The spacebar repeats the last command. The ESCape key will unselect everything you have selected.

To select items pick them individually or drag a box around them. If you start dragging from left to right you get only items fully inside the box. If you start dragging right to left you select anything even partly inside the box. If you pick individual items but are only able to select one, type PICKADD spacebar ON spacebar

Draw the round ended slots horizontally. Put in a circle, select it, click Copy and copy it across to the other end. Watch the bottom of the screen, it will tell you how far you have gone. Draw a rectangle to get the two sides. Select all 3 components and click on Trim. Click the bits you don't want and they disappear.

Select all four components of the finished slot and click Copy. Stick copies wherever you want.

Add the circle. Click circle, the default is centre then radius. Click for the centre, type in the radius.

Add the 45 degree rectangle. Select everything so far. Click Rotate. When it asks for the basepoint type Center (American spelling) then click on the circle. Type -45 for the angle, AutoCAD defaults to counter clockwise so you put in negative angles if you want clockwise.

Draw the other rectangle.

Select both rectangles and use Trim to lose the bits you don't want.

Select both rectangles and type Explode so they become lines.

To radius the corners click Fillet
Tell it the corner radius is 8 by typing R spacebar 8 spacebar
Click any two lines and get the fillets.
Press the space bar to repeat the last command, no need to do the r 8 bit again.