Hacking the Xaar 128 printhead

Powder and inkjet printing
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dragonator
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Re: Hacking the Xaar 128 printhead

Post by dragonator » Wed Feb 27, 2019 5:41 pm

Looking very nice. No obvious blurring or missing lines.

Is the speed currently limited by anything or are you printing at this speed because it is easier for now.

I am not really familiar with the damper. What is it's purpose. Is it there to smooth out the flow of ink you are pumping to the printhead?

davidk
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Re: Hacking the Xaar 128 printhead

Post by davidk » Wed Feb 27, 2019 7:28 pm

Hi Dragonator,

The speed can be much higher. However if I print fast and with much ink (all nozzles at once) the head starves. I suppose it's because my heads are scrapped and probably the internal filter are clogged. So, as I can't feed ink properly I'll print slow. And if I run slow there's no risk in crashing the head if media is too rise.

In theory the damper absorbs the ink pressure variations as you assumed. This particular damper has another function. It lets ink flow ONLY if there's a vacuum beneath it. Otherwise the ink will remain in the reservoir and tubing; reservoir is about 300mm above the head. So it allows me to put the ink reservoir up without the need of a vacuum pump. I don't want to put the reservoir under the printing plane, I need all to be up.

The print output is smooth if the head is at about 1...2mm above the media. Otherwise the print is misty. I have a blocked nozzle so I'm thinking of a multi-pass method that interlaces the nozzles so only one clogged nozzle won't matter.

Today was the 7th day since I filled with ink. So far all is working; if I use the priming pump for 1s then wipe gently the head before each print ALL prints are great except that single fully blocked nozzle. This ink adheres to electrostatic paint and all kind of plastic.

I need to find a way to interlace the printing, so a blocked nozzle to affect less the output. I'm working on that.

Braden
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Re: Hacking the Xaar 128 printhead

Post by Braden » Mon Mar 11, 2019 9:19 pm

Hey guys,

I was wondering if anyone could tell me what height difference they found worked the best relative to this picture in order to create the negative pressure the print head needs? I was thinking of having the print head about 10cm higher then the ink level?
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aengel
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Re: Hacking the Xaar 128 printhead

Post by aengel » Mon Apr 29, 2019 7:42 pm

Hi Macellen :

Most inkjet formulations allow very small amounts of solids in their mixtures, E.G. 2% solids.

Regarding your desire to use Kloroform or Acetone, you might consider diluting your test polymer or organic in Kloroform or Acetone first, and then adding Xaar approved head cleaning solution.

The Xaar approved head cleaning solution might tolerate your mixture, and allow you to prove your concept.

Today I am speculating about adding tiny amounts of monolayer type materials, i.e. silanes, to standard Xaar head cleaning solutions. Given that the Xaar head outputs picoliter amounts of liquid, and given that the amount of monolayer would be one part in 10,000 solution, I have been speculating that a crude monolayer might be coated?

Good luck, Allen.

aengel
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Re: Hacking the Xaar 128 printhead

Post by aengel » Mon Apr 29, 2019 7:48 pm

I appreciate the helpful and frank feedback from the many readers and contributors to this Xaar forum.

Here is another schematic of a driver board to drive the Xaar printhead. The Xaar printhead is delightful!

If you have a moment to eyeball this latest schematic, and provide feedback, I am grateful.

Please click on the drive.google link below to view a .png file of the schematic.

Thank you, Allen.

https://drive.google.com/file/d/1YEKABk ... sp=sharing

maxt
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Re: Hacking the Xaar 128 printhead

Post by maxt » Tue Apr 30, 2019 10:31 am

hello aengel,

thank you for sharing your design for the XAAR driver board. I'm fairly new to this topic and would like to ask you what is the reason for the dedicated "XAAR Power source" block which in other working schematics in not present.

Have you experimented with different inks ? if so, what is your esperience ? I found two XAAR-128 datasheets, one from 2017 lists the following compatible inks, water-based, oil-based, solvent-based. Then the same datasheet from 2018 (or 2019) which does not list anymore the water based inks as compatible. So I'm wondering what's the truth.

Several people here said that water won't work, but pure water won't work basically with any printhead because of too high surface tension, can't be easily jetted through microscopic nozzles. So has anyone tested this head with water based inks with lower surface tensions (e.g. water added with IPA) ?

The other puzzle are the UV inks. I could find UV inks which are sold as compatible with XAAR-128, but the datasheet does not list UV inks among the compatible inks. Has anyone succesfully printed with UV based inks ?

thank you in advance, Massimo

davidk
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Re: Hacking the Xaar 128 printhead

Post by davidk » Tue Apr 30, 2019 11:57 am

I use INX TRIANGLE MLD solvent inks. They dry slow so no risk of nozzle clogging. For capping you can make your own gasket from silicone rubber. My ink won't react with sillicones

aengel
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Joined: Fri Mar 16, 2018 2:05 pm

Re: Hacking the Xaar 128 printhead

Post by aengel » Tue Apr 30, 2019 1:55 pm

Hi Maxt :

What is the reason for the dedicated "XAAR Power source" block which in other working schematics in not present.

The schematic designer, Mr. M. Kamel, reviewed the many valuable posts by other YTEC3D contributors, and developed the block. Possibly Mr. Kamel will be available to freelance. He can be contacted at Upwork.com. I gave him positive feedback on their website.

Have you experimented with different inks ? if so, what is your experience ? I found two XAAR-128 datasheets, one from 2017 lists the following compatible inks, water-based, oil-based, solvent-based. Then the same datasheet from 2018 (or 2019) which does not list anymore the water based inks as compatible. So I'm wondering what's the truth.

There are several ink jet formulators in the Western countries, and in Asia. I would suggest trialing their inks before attempting to formulate custom inks. Inkjet inks are difficult to formulate.

Several people here said that water won't work, but pure water won't work basically with any printhead because of too high surface tension, can't be easily jetted through microscopic nozzles. So has anyone tested this head with water based inks with lower surface tensions (e.g. water added with IPA) ?

HP adds copious amounts of Triton X100 surfactant to their water based inks to knock down the surface tension.

The other puzzle are the UV inks. I could find UV inks which are sold as compatible with XAAR-128, but the datasheet does not list UV inks among the compatible inks. Has anyone successfully printed with UV based inks ?

Low viscosity uv resins are available from Allnex and Sartomer. Formulations have been published, but they are difficult to find. Currently our company is not pursuing uv inks for inkjet. Good luck, Allen.

maxt
Posts: 27
Joined: Fri Apr 26, 2019 10:38 am

Re: Hacking the Xaar 128 printhead

Post by maxt » Wed May 01, 2019 6:20 pm

Hi,

I'm not intending to formulate my inks, but I'd like to avoid buying water based inks (whomever formulated them) if they will ruin a 200€ printhead.
On the other hand, if neither water based inks nor UV inks can work with this head, then this head is not suited for me (hope it is)

regards
Massimo

Wonko
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Re: Hacking the Xaar 128 printhead

Post by Wonko » Fri May 03, 2019 12:29 pm

I think Tritron V Photon black ink is UV ink that is recommended by Xaar for the 128. Not sure though.

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