An intro to Pen Plotters (2019)

This is a fun article but the author really should update it to include the AxiDraw[1] which is a modern, off the shelf, pen plotter. It makes EPIC plots because you can use what ever pen you want in it (as opposed to old HP plotters that needed HP pens). Check out #plottertwitter on Twitter for some really amazing things folks have done.

[1] https://shop.evilmadscientist.com/productsmenu/846

I really missed out back in the early 2000s when companies were throwing away their old plotters and replacing them with massive inkjet printers. I've since gotten into 3D printing as a hobby, and recently have been playing around with attaching a pen to the printhead. This works quite well, and is more fun than I expected. If you're looking to get into CNC pen drawing, an inexpensive 3D printer might be the way to go, although I can't fit an entire leaf of paper on mine, so need to limit the size of my drawings. I've also experimented with extruding plastic directly onto the paper which surprisingly works without warping, but I haven't come up with any creative use for it yet.

As an example of what you can do, here is someone who has gone beyond just attaching a pen like I did, and actually integrating a pen changer to use multiple colors: https://youtu.be/pxt_TbyBImc

Errata: HPGL, the language referenced by the article as having been “forgotten by most operating systems” and used by most pen plotters, is still in use for every vinyl cutter I’ve ever used.

In fact, vinyl cutters come with a pen holder and are also single-pen plotters out of the box. They’re a tool changing mechanism and a couple of firmware command implementations away from being capable of multiple colors - or you could just manually change the color of the pen and re-run the same paper through once for each color.

A few years back some enterprising merchants in China were selling these to kids in elementary school to do their homework. After all a significant portion of homework is literally copying characters / passages over and over again. They came with software that allows you to train it with your own handwriting so teachers cannot tell. It was amazing.

Man how far the world has moved on. I mean the stuff described here still works and is very cool. But there's a whole hobbyist world now built around SVG and new plotters like the AxiDraw. Check out #plottertwitter for a lot of examples.

https://twitter.com/hashtag/plottertwitter?lang=en

The author mentions, “Watch out for HPIB-only plotters!” — I forgot to take that advice when I bought a plotter from a scrap shop a few years back and thought I was completely out of luck. Spent a fair amount of time googling, and I ended up building an HPIB-to-serial bridge using an Arduino to get life out of the machine. Works just fine now! I’ve been meaning to write up how that works in case anyone’s in a similar disposition.

I built an interesting Bi-Polar Plotter with multi-pen capabilities this year. Really cool to look at. :) https://hackaday.io/project/177633-dual-disc-polar-printer

Can someone speak a little bit to the software toolchain for something like Axidraw? Is it SVG converted to GCode? I've build some of these types of machines for other pick and place tasks for my own needs, so just curious what in the opensourse world they are leveraging.

I'm trying to do hard copy paper backups of data onto WORM yet human readable bound paper that cannot be lost or removed from the book without evidence of tampering.

I have looked at pen plotters, handheld inkjet printers, and wondered about feeding a paperback print-on-demand printer a PDF that I generated.

Since I cannot afford an espresso book machine, I have tried to use a cheap Chinese knock-off pen plotter to try to write text from the computer directly onto a notebook journal page. The belt is too cheap and slippy so it sits there collecting dust.

One of these days I will have to break down and buy the axi draw and see if that one will enable me to print onto actual journal pages.

Any suggestions to effect such a goal that cross your mind, dear reader, I would be open to.

Back in the 80’s I worked at a company that sold and installed pen plotters (both desktop and large format) along with the CAD software and workstations to run them.

It was always a PITA to attach them because they always used RS232 serial ports and each vendor used a different arrangement of pins. You usually had to customize each connector, removing pins and soldering others together.

Still they were lots of fun to watch. People who weren’t even in the market for them loved to watch them work. It was like watching a little critter run around frantically on the page drawing an image. With each little stroke the image grew. It was a very relatable process. It kind of reminds me of watching a Roomba clean a room.

Damnit, quit posting these things and driving up the costs of HP and Roland plotters! Haha.

I recently have gotten into pen plotting (haven't done anything with this new found interest in the flesh yet), and it seems like a really fun mix of hardware + software + art.

"HPGL or HPGL/2"

It's been a long time since seeing the version like this. It seems more like they are halving the original. Anyone have a back story on this style of versioning?

Also, trying to copy that highlighted text from the Medium article is click-jacked/mouse-up-jacked/whatever to some lame social pop-up. It prevented me from highlighting at first, so a simple click-drag-highlight-keep-clicking-keyboard-shortcut-for-copy before releasing the mouse button. FUCK YOU!!!

Entirely too long ago I ended up using a pen plotter for two physics projects. In the second one, I built an extraordinarily slow scanner out of a plotter and a light pen. Whew. Worked, though.

This was a great intro! Makes me want to get a pen plotter while I can, and it's cheap to do.

I love pen plotters. In the 80's, and actually a ways into the 90's, I used them in tandem with CAD systems to do a variety of manufacturing and detail drawing related tasks. The drawings part is what you would imagine. It's a ton of vectors that add up to an engineering or architectural drawing.

The precision of these machines is actually quite good. When used with vellum paper, one can make overlays or underlays for inspection, layout and other tasks. An X,Y plotter will be more uniform than a roll plotter, but the roll plotters can handle very large sheets in one axis. Usually, a small factor can be used to compensate for whatever difference there is between the roller and the other linear axis. I remember it being small, fraction of a percent.

Over / underlay drawings, along with check drawings of various kinds were the daily driver use case. For the check drawings, ordinary paper worked fine. Vellum, has better characteristics for precision work. It won't stretch and can be handled and tolerate some shop grease and grime in a pinch when thicker grades are used. I recommend it for archives and or just that serious tech look. If you want a very seriously sharp drawing, a fine pen can produce amazing line art! There is almost no ink bleed.

Once, I ended up on a contract to make parts for Boeing and the shop I was in at the time had no real certifications, so Boeing sent me a 1:1 camera produced image of the part. And it was from a CAD system! Had I been able to get the file, I would have produced the part for them quick and easy. Just use the CAD data to drive a laser and one and done, but no.

So, I ended up taping the 1:1 scale image to a large inspection table, taking points, using a pen plotter, with compensation factors to get max precision, vellum paper, and laboriously recreated the shape and overlaid it to insure accuracy. This took a very long time, but it was actually very satisfying to do.

Another odd use popped up one time too.

There was a group of parts that formed an assembly. This was before nesting and optimization software was common for sheet metal turret punch and laser machines.

I used a plotter to produce all the flat shapes of all the parts, and abused a pen by drawing over profile edges enough times that the paper would tear / cut easily. Sat down at a table and shuffled them, until they would just fit into the largest possible sheet. That was kind of amazing. Do it once, save X square inches. Do it again, lose Y square inches. Again, Save, save, lose, save... eventually finding an arrangement that saved a ton! The software and computing systems really were not up to doing this at the time. Or, were but the applications were ultra expensive. So it took an hour to do it old school.

Used a Polaroid camera to capture that layout and reproduce it in the CAD system with precision to allow for optimal shared profile edge cuts and such.

Then came punching it out of the metal! Several thousand punch operations were needed, and that was another optimization problem and it was useful to do the same kind of iterative process, but machine time was expensive, so I used a pen plotter. Pen changes mapped to tool changes reasonably, and double drawing some entities mapped to other machine attributes. All in all, after a few basic constructs were mapped out, I had a very representative simulator that did produce useful visual output and the motion could be evaluated for other purposes, like sheet snagging and or just potential cosmetic issues.

Spent a few days sorting and plotting. Got 10 minutes of machine time down to a little under 4 minutes.

A year or two later, after I had left a friend saw the company buy the high end nesting and optimizing software. It was able to get another minute out of that job, and was able to do so in 10 to 15 minutes of computing. I think this was called SigmaNest and I forget what the tool path optimizer was called...

The work I did took about 4 days!

All that aside, I find pen plots, the noises, watching the paper move, all of it really satisfying. The better plotters are just wonderful machines that nail their purpose. Fun to see. Good tech, if sort of useless now.

If you want, you can use an old 3D printer as a pen plotter!

I have done this on mine, and it works very well. The accuracy is comparable, but paper sizes may be limited by the printer build area.

All one needs is Z dimensions to handle PU and PD, and G0, G1, G2, G3 to handle the basic lines, moves, arcs.

You won't get any of the fancy fills that way, but Inkscape can generate those as a combination of lines and arcs, and the overall effect is the same, only the plotters are generally much quicker than the 3D printers can be.

Overall look, with a good pen, vellum paper, is comparable as well.