On Sun, 9/22/13, Marshland Engineering <marshl...@marshland.co.nz> wrote:
I have a A3 HP plotter and was wondering if this be adapted to use a knife for making plastic stencils ? --------------------- Yes, lots of people have done that. There are knife holders made to fit in place of the pen. You may have to tie the clamp closed so it won't pop out from the pull on the blade and it takes some careful attention (typically from the cutting software) to always turn the right ways so the knife follows along properly instead of cutting loops out of the non-waste areas when making tight turns. Search youtube for hp plotter vinyl cutter Another thing is since the knife holders generally don't fit the holder stations (and if it's tied into the carriage), you have to ensure the HPGL code has no commands to store or change pens. If the clip holds the knife holder securely you can physically modify the holder station and plotter housing so pen change commands won't matter. A very nice thing about those old HP plotters is they're completely system agnostic. All they need is a serial port they can be set to match communication with. What was very nice about PLT files was they were usually small files that could be put on a floppy then mailed and an exact plot run out by the recipient. Easier than rolling up a large drawing and hoping United States Pet Snail didn't fold it in half. Sending an HPGL PLT file to the plotter is easy. With any Microsoft OS, all you need is a command prompt and use the COPY command to send the file to the right serial port. Should work the same way in Linux by sending the file as text data to the serial port. I don't know if the plotters can be "drip fed" commands in realtime or if the entire plot has to be created then sent. AFAIK the plotter likely ACKs the receipt of each command then RTS the next. I just made the plt files and used my batch file in a command prompt window from XP. It worked so I didn't bother with the gritty details. ;-) HPGL files use only standard "low" ASCII characters. HPGL/2 mixes in some extended ASCII characters so to write them by hand you need a text editor with extended ASCII support. Might have to send them to the port as binary data instead of text. I used to have an HP 7470 which I used to plot cutting patterns for a bandsaw. Thought I still had the batch files I used to print them, couldn't find them, unless they're on another computer. If you want to get fancy you could build a knife with powered turning, but figuring out how to coordinate it with the HPGL code would be an issue. A "wedge" between the computer and plotter and knife turn commands interleaved with the standard HPGL code could work, with the "wedge" running interception so only valid HPGL goes to the plotter and the knife commands go to that system. Could just use the mechanism and motors and completely replace the electronics to use with a powered rotation knife as a 3.5 axis CNC. (The .5 for knife up/down.) One mechanical issue with those plotters which slide the paper back and forth is the pinch rollers get flat spotted if someone ignores the warning label to not leave the paper lever in the loaded position when not using the plotter. I tried to find new rollers for mine but never could. I thought about making a mold to cast semi-rigid urethane onto the old roller cores but it wasn't that vital, just put some tiny wiggles in the lines it drew. ------------------------------------------------------------------------------ LIMITED TIME SALE - Full Year of Microsoft Training For Just $49.99! 1,500+ hours of tutorials including VisualStudio 2012, Windows 8, SharePoint 2013, SQL 2012, MVC 4, more. BEST VALUE: New Multi-Library Power Pack includes Mobile, Cloud, Java, and UX Design. Lowest price ever! Ends 9/20/13. http://pubads.g.doubleclick.net/gampad/clk?id=58041151&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
