AutoCad Help

Hey So if anyone is handy with autocad I need some help. I need to create a DXF or DWG file. What I am needing to make is a 101.6mm diameter disk filled completely filled with the pattern you see here. Each of these tiny circles are 20 microns or .02 mm in dia with a spacing of .04mm between them. If someone can help me to make this pattern in AutoCad I would greatly appreciate it.

If you don't get anything, post a reminder Monday morning and I'll see what I can do.

The simple way would be to make two rectangular arrays (since they are offset and not all "in line").

And, I'd probably make the pattern in a 101.6 rectangualr box. Then draw a circle from the center of the box and trim out the extras.

To draw the little circles, type "donut" in the command line. Use a zero inner dia with a .02 outer dia. You could put the first one at 0,0 (or where ever you want).

If they need to be blue, hit the escape key. Then click on that first donut and then right click. Choose properties and the properties dialog box will appear. Select color (blue). Then click into the next box below that (or sometimes the color won't "take"). Then close the properties dialog box.

Now type "array" in the command line and choose "rectangular". After that, I'd suggest you choose "count" and it will ask for how many horizonal and vertical items you want. You'll have to experiment here to get the amount you want.

You might have to do this twice to get another array that is offset (or you could use the "Copy" command and move everthing over half the width and height of the array spacing.....again, you may want to experiment).

Then I'd draw the 101.6 circle over the entire thing (type "circle") and trim away the unwanted donuts using erase command.

This is just quick and from memory (I don't have AutoCAD on this PC). I am sure there's other ways to do this but this may get you started unless someone else can provide more detailed steps.

ps--THIS may help too.

Yeah, it would take me less than 5 minutes to do this...at work.

The issue I see is that you're going to be pushing the resolution limits of AutoCAD, which is 1/256 of an inch.

what's the start point of the pattern? I mean, is it random on the disk, or the center of one of the pattern circles centered on the disk, or........

happened to bring the work laptop home today.

was able to create a grid with the pattern large enough for the disk. units for the file are in mm. bit of a cumbersome file. if you tried to do an array of just two of the cirlces, it exceeded the array limits of 100000 (was ~6.5million). had to create a block of the pattern then do about 30x30 of the block.

mind if I ask the purpose? Just thinking that if the point is to make holes on this disk, whatever tool you're using to make them might read the file better if it were based on just center points. we're talking about ~10 million of these little circles on the disk. I tried to explode the blocks and it crashed ACAD.

another approach could be to create a custom pattern. might not be very useful, though.

^this. I have Solid Edge, and I could make this in seconds except its a bajillion holes and will make just about any cad program on any computer hate life.

Yeah thats the problem i was running into, its just so many elements. The advice given here I think will be helpful, thanks.

Also how do I know if units are in mm or in? Where do I specify that in Autocad?

The purpose is that I need to make the dwg/dxf file so that some company is going to make each of those circles raised cylinders, with a height of .01mm

Our of curiosity... IF you created the dxf, could any CAM software read this? Could said CAM software create this? What's the G-code line limit? ~4.5 million discrete points usually means a lot of code.

And the question everyone wants to see answered: WTF is this for?

fritzsch wrote: Yeah thats the problem i was running into, its just so many elements. The advice given here I think will be helpful, thanks. Also how do I know if units are in mm or in? Where do I specify that in Autocad? The purpose is that I need to make the dwg/dxf file so that some company is going to make each of those circles raised cylinders, with a height of .01mm

ddunits in acad lets you set the units for the file. or you go through the pulldown but the command line is quicker/easier.

ok, this is the part where exactly how they're going to do that is crucial. I have a feeling that whatever software/hardware combo they're using to make this part is going to have to process it in the same way i set up my array: a smaller subset of the pattern that gets run in one go, then that subset gets run again using a new precise basepoint one subset pattern over.

i'm very curious about what fab hardware they're going to use to make such small work.

Boooooooo! No update!

Ya got me curious.

well I was able to get the millions of circle successfully! the computer absolutely hated it, it took many minutes for AutoCad to respond if I wanted to so much as pan or zoom at all.

I am creating this file for a professors research, I don't know a whole lot about it. but I think it is going to be made using a positive tone photoresist and silicon etching.

So I have this massive block of circle, how do I trim them into a circle. I was having trouble experimenting with my model since it was so slow. Advice on the trim function would be nice

anyone with trim advice? do I have to explode the array and delete the unwanted elements?

I think it's time to ask (very respectfully of course) the prof if whoever is getting this file to execute the process realizes how much of a pain it is. my thought process is that if this file is this hard to manipulate, how are they going to do just that to produce?