Newbie- Want to import 2D DXF & convert it to 2D step & dir

[cnc2]

Originally Posted by Superman My last word for you do not be surprised about the speed of bi-directional drum plotter to draw a 1000mm * 500mm rectangle = perimeter is 3000mm speeds range from 25mm-500mm per second so to draw a 1000 * 500 rectangle = 6.0 seconds reference is http://easyaid.en.ecplaza.net/1.asp MODEL:HX720 720mm 630X unlimited length note! you can use a pen instead of a vinyl cutter Time to plot uni-directional will be unbeleivable ( 2 dots per across pass @ 500mm apart - to give a dot pitch of 0.25mm then 1000mm= 250 passes * 500mm travel @ 500mm per second = 250 seconds = 4.17 minutes Time will increase if you want dots closer together if you want a "line or arc"

Thanks Superman this message was an eye opener !

I focused on the software and forgot about the hardware limits, after more figuring i found that my first figure that had the drum going 200 rpm needed the head to print more than 100 000 dot per minute for one dot per line & 0.25mm between lines (IMPOSSIBLE with a traveling print head) even if i want the lines 2mm from each other it would still be impossible...now i see the benefits of going b-directional, only a beginner like me could under-estimate it.

I think making the machine bi-directional won't be too hard i can add a drum on each side of the printing drum for preventing the paper from "cleaning the floor"...HPGL is back in business.

by the way Where on "earth" are you?

I'm in Algiers, Algeria.

Thanks !

cnc2.

[Dennis Bohlke]

If you use a by directional drum my USB CamPod and SuperCamXp program can get you running straight away. With HPGL or DXF files.
http://www.super-tech.com/root/grp.asp?p1=CamPod

I got my original ideas watching a drum plotter pen plotting autocad drawings. That was a huston instruments plotter that had little rollers on each side with a cam lever to hold the paper down.

Dennis
www.super-tech.com

[cnc2]

Originally Posted by Dennis Bohlke If you use a by directional drum my USB CamPod and SuperCamXp program can get you running straight away. With HPGL or DXF files. http://www.super-tech.com/root/grp.asp?p1=CamPod I got my original ideas watching a drum plotter pen plotting autocad drawings. That was a huston instruments plotter that had little rollers on each side with a cam lever to hold the paper down. Dennis www.super-tech.com

Thanks for your reply Dennis !

I've got a lot of respect to the level you've reached & how easy you've made it for people, setting'em up & running with a complete package, unfortunately i have to write the soft by myself, it's for my school's final project & if i find it too hard to get it working i'll have to find myself another project that i'll be able to achive.

Since i'm too far from the US, shipping the CamPod will double its price, that's why i'll have to assemble the electronics by myself (from common DIY stepper board projects) & hope it to work.

Thanks !

cnc2.

[Dennis Bohlke]

If you do not concern your self with accelleration and decelleration it greatly simplifies the task.

And with HPGL all the math can be integer math.

Best Wishes

Dennis
www.super-tech.com

[cnc2]

Originally Posted by Dennis Bohlke If you do not concern your self with accelleration and decelleration it greatly simplifies the task. And with HPGL all the math can be integer math. Best Wishes Dennis www.super-tech.com

Thanks a lot for those tips Dennis, i'll keep'em in mind.

Thanks !

cnc2.

[bdahmet]

Hi CNC2,
now I understand.
Let me summarize:
First you wanted to build a drum "printer". By having a pen "peck" (Like a woodpecker) onto the paper instead of some "inkjet drops".
At this time, the idea of having the drum turn in one direction only was OK. Like a regular printer. Then the idea of using bitmaps was better suited to your needs as "theoretically" every pixel in the bitmap would somehow (scaled or not scaled) correspond to your pecks.

A Drum pen plotter, mostly used for vinyl self adhesive film cutting uses mainly HPGL. İt is easier tu inerpret as it gives you X-Y positions some commands (circle center - radius - arc etc) and whether the pen is up or down, speed etc.

In this case the paper will have to move forward and back, but fortunately this is achieved by friction rollers. So you dont need two rollers that are synchronized. It is sufficient if you squeeze the paper inbetween without friction.

Acceleration: There's no such thing as no acceleration as long as you are not talking about objects standing still. If you want to have an object change its state from standing still to any speed, there is a time that the object accelerates.

On the other hand I dont know what your main task for the school is but you should drive your "plotter/printer" through another software program. As far as I have lerned here is that it is espcially with windows, a very difficult task, as windows is not a realtime operating system (as opposed to DOS or Linux).
So your commands given from your apllication are qued bfore given out to the printer port... (anyone correct me if I'm wrong)
Try MACH3 , there you can adjust the acceleration ramps, stepper speed, you can maybe have your "pecker" defined like a laseer and its pulses. I mean the program is infinitely customizable....

Give it a thought.

Ahmet