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Topic: L-Mark LK-320P heat shrink/tube/label printer (Read 34853 times) previous topic - next topic

L-Mark LK-320P heat shrink/tube/label printer

We've been on a multiyear quest to make a durable, affordable, usable probe cable for the Bus Pirate. The one currently sold by Seeed is inexpensive (good) but not very long lasting or particularly usable (not good). I typically use male:female individual probe wires.

With the Bus Pirate education kit almost sorted, we MUST have a better probe before launch. Ideally it will be something with male ends that stick into a breadboard and labels on each probe.

A few times over the past year we've tried to get a new cable put together with labeled probes, but various barriers and misunderstandings about heat shrink and cable labeling always got in the way. It's beyond time to bite the bullet and make an example to shop around for quotes.

This is a opportunity to buy a new toy: a shrink tube printer. At first I looked at several DYMO RHINO models. They are cheap in the US, but extremely expensive in China. All use special cartridges of shrink tube that run about $30 for 5 feet. To compare - 200meters of shrink tube is about $5 in Huaqiangbei... There's also the risk that none of the sizes of shrink tube cartridges available would be adequate or the right color. I mean, what if we want hot pink labels?

A Taobao dealer selling the BYMO RHINO referred us to a professional heat shrink printer that was only about $100 more expensive. In the end the professional setup was less than $40 more expensive because we bought cheap heat shrink in a bunch of sizes and colors instead of the expensive cartridges used by the RHINO.

We chose the L-Mark LK-320P over other brands because it's exported and very google-able. Some of the other options were more enticing, but seemed less known which could lead to ribbon supply issues later. The "P" version means it has a USB port and connects to a computer, where it's much easier to deal with the Chinese interface (and hack?). We paid about $250 for the Chinese version of the machine. You can find the English export version on Alibaba for $400+. We ordered it from a company in northwestern Shenzhen (Bao'on) in the morning, and it arrived in the evening.
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Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #1
In the box we got the printer, one label cartridge, one black acetate transfer ribbon (called color tape in Chinese), software, manual, and some cables.

We tested it out with the label cartridge first. Not only is the interface (of this version) in Chinese, it's about the clunkiest thing ever. After some fumbling we spit out a few labels with some confusions about what word too long errors and paragraph settings meant.

Next we removed the labels and stuck in some yellow heat shrink tube picked up yesterday in Huaqiangbei. Did you know most heat tube is already printed? I had never noticed before until I tried to find blank tube. I ended up with something with small printing, today I can pick up a reel we ordered from the factory with no printing.

We printed a few Vpu (voltage pullup probe) labels for the Bus Pirate cable. The tube seemed to wander around and printing was inconsistent. Then we realized the label cartridge has a plastic arm that works as a feeder for the tube, holding it down during printing. It's not clear if this is intentional, and it isn't mentioned in the manual. With the tube threaded through the cartridge things started to work great.

The interface, even if not in Chinese, is wretched. We decided to give the PC connection option a shot. Drivers for the USB to Serial chip (by failed on Windows 7. Ok. Drag out the wonky Windows XP netbook and everything installs fine.

The printer enumerates as a USB to serial device so it's probably very sniffable and hackable. Open it up, bring out the serial, and use a modern converter chip with updated drivers. That presents a minor issue as the software seems to look for it's specialized drivers (no way to set a serial port manually), but sniffing would be very easy and a simple app to send commands from a CSV spreadsheet could be whipped up in no time... But I digress, none of this gets us closer to a sample Bus Pirate probe cable.
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Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #2
The software isn't great, but it's way better than the terrible menus and poorly debounced keyboard on the machine itself. Each heat shrink label tube diameter, length, font size, cut type (half, line, none), darkness, repetitions, etc are set in a spreadsheet like interface. It's in Chinese but you only need to recognize a few characters to get the basics, mostly cut type. There's an option to import a spreadsheet of labels, which seems like the easiest option, but as of yet we've found no example of the format needed (and the native file is binary which gives no hints). There's an English version of the 320/330 so the software might be available in English, but the downloads on L-Mark's English website fail.

We were up and printing meters of probe labels in a few minutes with the PC connect software.

And then the acetate transfer ribbon (ink, basically) broke. Just snapped. And we had no spares. Using a little screw driver and the smallest fingers in the room we pried open the ribbon cartridge with minimal damage. We tied the ribbon back together and did what we could to rethread it properly. Amazingly this worked!

One thing we spotted in the cartridge is possibly an RFID chip to either ID the type of ribbon, or worse, to prevent third party replacements. The ribbon isn't "cheap" at ~$6 for 80meters. Other machines are much cheaper. However given that we could open the cassette and repair it with minimal damage, we'll probably just respool it with cheap (and plentiful, and high quality) acetate ribbon that's used all over Huaqiangbei to print fake cell phone battery labels with the Postek G-3106 or C-168 (our model).

Verdict: it works, and we're closer to a probe cable I like. Worth the money? Sure, especially if I bought it 12 months ago and didn't waste so much time with false starts on the cables this past year. I wouldn't buy it from Alibaba for $400, that's for sure, and I would stay away unless you've got some basic Chinese reading skills or a friend who can help translate.
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Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #3
The end probe with GRND on it looks handy. No more "is that cable white or grey"..

Are you going to sell these loose or are you only going to ship them with the "education" kit?

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #4
I'll give away sets if theres interest. The new cables at Seeed will have them, and it will aslo be the cable in the education kit.
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Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #5
Does it allow custom font (i.e. wingdings) or has it some things built in?

Besides the crapiness of the machine it looks a cool addition to your workshop.

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #6
since you are looking on things like this, can those be used to label ethernet cables? (big enought to pull over the contact, and shrink enough to sit good?)

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #7
[quote author="neslekkim"]since you are looking on things like this, can those be used to label ethernet cables? (big enought to pull over the contact, and shrink enough to sit good?)[/quote]

You have sheet of special adhesives for this. about 75% of the adhesive is transparant and 25% is white. After printing you can wrap them around the cable. A random link to the sheets:

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #8
and that works?, we have tried some brother/dymo but the adhesive loosens and makes an sticky goo on the wires, so I thought something heatshrink based would be nice.

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #9
@Neslekkim - Proper trade labels for use with proper industrial printers like Brady, etc. work pretty well. As Sjaak pointed out, they have a clear section as a portion of the label and that wraps over the print to laminate it. It works OK for many applications, but heatshrink or hard plastic labels are better in some applications. Yes they can slip and get messy in some applications, but better than normal commerical stuff like Brother / Dymo.The industrial stuff from Brady, etc. is not cheap though.  You can also use Raychem (and others) type of heatshrink sleeves such as these http:// and many of these types can be used with standard old-fashioned Epsom dot-matrix printers when you use a special ribbon. The print becomes permanent when it is heated / shrunk and will resist even diesel, solvents, etc. Lots of different types / prices, so check around the trade suppliers.

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #10
[quote author="neslekkim"]and that works?, we have tried some brother/dymo but the adhesive loosens and makes an sticky goo on the wires, so I thought something heatshrink based would be nice.[/quote]

Not had problems with them. removing them gets very messy though ;)

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #11
Some ideas:
- If you can open it up and directly sniff out the data lines, you can write you own program for it. You have to try bunch of different settings and match them up with the sniffed signal. Another way can be using the software sniffers in Linux and running an XP virtual machine on top for the program. Not sure if better or possible but something to think about.
- RFID chip: Probably it stores some sort of ID number so that the printer can adjust the settings of the printer. Saw a similar thing on the crappy mobile printer I bought recently. It has a paper cartridge with black squares and couple of light sensors on the machine. According to the manual, it uses the sensors to identify the type of paper and adjust heater elements and other stuff. Anyways, the RFID data can be read, it's probably 125 kHz, then you can program your own RFID stickers and use any cartridge.

Nice to hear from you Ian!

Re: L-Mark LK-320P heat shrink/tube/label printer

Reply #12
Yes, the later model Brady Industrial printers use RFID on the ribbon rolls, as do other professional print systems, it's mainly to identify the type of ribbon, film, etc. to save you having to manual enter the details - and probably so they can charge more for their own branded stuff. It is possible you may be able to just peel it off and use it over and over with another better/cheaper/etc. cartridge.

Printing quality

Reply #13
Print quality

Print quality seems to depend heavily on the shrink tube. Cheap, highly flexible tubes that compress flat in the printer look beautiful. Expensive, thick tubes range from fair to crap.


We picked up 20 meters yellow and 20 meters white high quality shrink tubing, 3.2mm diameter, 3:1 shrink ratio on Taobao for $0.20 per meter. Most tube has some kind of marking on it already, but this tube is totally blank. We thought it would be perfect for printing, but it's too stiff and doesn't hit the print head properly. The white tube printed ok, but the yellow tube looks awful.


Next we grabbed a reel (200 meters) of white and yellow shrink tube from Huaqiangbei for less than $7.00 per reel. This stuff is very thin, flexible, and the prints look great. It already has marking along one side, but if we hold it right it stays on the back of the tube and doesn't interfere with the print. It's a pain, but it's just a prototype.


From left to right: expensive white, expensive yellow, cheap white, cheap yellow.

Sample cables


Here's a sample cable in yellow, and one in white. The white one looks cleaner, but the yellow looks a bit cooler.

Additionally, there's two styles of printing - one justified to the left edge of the pin housing, the other centered in the shrink tube. Both cables have half of each. I like the left justified better because the print is much larger and more readable over the crimp housing, however it's also "upside down". I'd prefer right justified but the label printer doesn't have that as an option.

Hopefully for the final cable we can also source an extra long housing that's easier to handle.

I'd really appreciate your feed back on:
1. Yellow or white tubing?
2. Left, right, or center justified printing?

I have a bunch of sample tubes I made while experimenting, and you can have a set in exchange for your opinion :)
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L-Mark LK-320P heat shrink/tube/label printer

Reply #14
Can't you right justify by sliding it on upside down?

I prefer the left justified.  I find my eyes start at the end of the material anyway, when they encounter nothing the blank space feels confusing.

I guess printing on both sides is out of the question?

Just for reference, this is what Xilinx does.  I guess the real question is when are you looking at the labels?  Mostly during hookup, once they're in place do you read them?

For making instructions photos I guess it is handy to have them at the circuit, but perhaps colour is enough?

I'd also like to see a little more heat-shrink too, longer lengths just feel more robust (provided it is thick enough)

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