Building a pen plotter..out of a pen plotter - Page 1
Forum section: electronics / projects

author: ChristofferB
author_rank: Frequent Contributor
timestamp: February 13, 2018, 06:14:55 pm
content: perhaps 7 years ago, i tore down an old Goetz graph plotter cause it didn't respond to any input, and now I really need a graph plotter..I saved the head assembly containing all the mechanics;- stepper and cogs that drive the paper- pulley/wheel system that drives the pens- dc motors to move the pens- WRITE solenoids that lowers the pen holders- multiturn pots that indicates pen position.I'm figuring that's easily the hardest things to DIY, so i may wanna try building a pen plotter from this.Any opinions on what the easiest way of getting this kneaded into a plotter? i'm thinking either a microcontroller (arduino) for both pen movement and paper feed, analog control for everything, or analog constant speed (changeable) for paper feed and then pen movement by microcontroller.Which way would you go?By the way, the pen motors are really nice Maxon DC motors, 2522.846. Does anyone know what voltage to feed those?thanks!

author: nanofrog
author_rank: Super Contributor
timestamp: February 13, 2018, 06:48:01 pm
content: What follows the xxxx.846- ?The two digits that follow the hyphen is the voltage. So if it's 2522.446-12.xxx-xxx, then it's 12VDC.

author: bkucenski
author_rank: Contributor
timestamp: February 13, 2018, 08:57:56 pm
content: Pen plotters are cheap now.https://www.monoprice.com/product?p_id=13960&gclid=CjwKCAiAtorUBRBnEiwAfcp_YxYvwZo6dEIGjJtCb8Ef-K0Gbb-5OLeLVzCPyb8NcFt5alDmKqm3GRoCYB0QAvD_BwE$200 for one that will work out of the box.The Arduino controller boards are around $10 on Aliexpress. And the GRBL software for the Arduino is free.Stepper motors are used rather than Pots to control position. While some plotters and laser engravers use explicit switches that the mechanism hits to indicate it's reached the end, you can also measure the stepper motor to see when it's not actually moving and tell that it's reached the end that way.I bought a Makeblock laser engraver and mounted it to a 24" x 24" slab of wood from Home Depot as was able to laser in the guide.You might be able to make use of some of the parts from something 7 years old, but from the list of parts, it sounds really archaic.Modern controllers also run the motors at 12V. That hasn't really changed. But simple DC motors are just really going to be more difficult than just using steppers with the well defined and implemented GRBL standard.Buying a premade kit will get you familiar with all the modern parts and then in you're feeling ambitious you could try building your own with the remains of your old one.https://photos.app.goo.gl/cctuOprg5T36hgCJ3This is the laser engraver by the same company. Once, properly mounted, it was able to laser engrave its own guide with 1/2", 1" and 2" squares.

author: rstofer
author_rank: Super Contributor
timestamp: February 14, 2018, 03:16:33 am
content: I needed a replacement for the CalComp 1627 drum plotter but I had no control over the step commands being sent by the CPU. I had to replicate it perfectly in terms of motion commands. So, I ran the step commands into an mbed LPC1768 processor and converted them to HPGL commands that are understood by many printers. I sent my strings to a networked LaserJet.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: February 14, 2018, 07:59:15 pm
content: Thanks for the replies! Sorry, should have clarified, it's not a graphical plotter - it's plotting voltage graphs on infinite rolls of graph paper, like a very slow scanning "analog stotage" oscilloscope.I think i'll look into driving everything with a single MCU. it should be able to handle a stepper and some motor run/stop logic.Again, thanks!

author: Leo Ice
author_rank: Newbie
timestamp: March 09, 2018, 01:39:40 pm
content: Hi guy! Look I am interesting laser engravers now nad wanna to do one project with merbau wood... One guy recommended me to use one of two engravers. it is Meterk Laser Engraver Printer 1500mW and WER 1500mW Miniature DIY Laser Engraving... What can u say about it? Whitch is better? If u don't know too pls send me a message) Thank you!