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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Joined: Sun Mar 12, 2017 6:48 pm

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
Posts: 3
Joined: Sun Aug 12, 2018 5:42 pm

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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