#MakiBox A6 Pellet Drive Dry Run

2021-08-27 21:15 by Jonathan Buford (comments: 0)

#MakiBox A6 Pellet Drive Dry Run

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We started to test the assembled pellet drive tonight, but found that it was getting intermittently stuck at one point. After looking into (literally) the barrel to see where the pellets are getting jammed, we were able to improve the problem, but not eliminate it tonight. Basically, they are getting stuck where the transition is too sudden. We will change the barrel design again tomorrow and give it another go.

 

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Comment

mziol (Twitter) responded:

 
Jon,

Could you get a hold of me? I worked on something like this back in college (pellet feeding system) and as a "stakeholder" (having ordered a machine already) I'd love to help with any of the experience I can offer.

-Michael

ludzinc responded:
 
Hi,

Not trying to be nasty / smart, but have you researched how this is done in industry?

If you take a look at an injection moulding machine, you'll see that they heat a long zone along the feed nozzle - so that the screw is pushing a liquid, not pellets.

Is it time to shelve the pellet feed for now, and focus on printing? Once that is done, then return to the pellet feed afterwards? As a final suggestion, collar heaters are plentiful out there, and a mains rated one will provide all the heat you need.

Best of luck, don't let scope creep kill this project!

Jonathan Buford responded:
 
@ludzinc - Check out this new post for a reply. http://makibox.com/makibox-a6-pellet-drive-hot-end-plastic-actio

I think if we follow how things have been done in industry, we will not be able to innovate. I have spent many, many hours around the equipment and processes at factories, so am aware of the status quo, but a mains connected heater sounds akin to the trying to swatting a fly with a sledgehammer. It might get the job done, but it will neither be cheap or well suited to the needs of the application.

Based on our tests, you only need around 60W peak, and a holding heat of around 5-15W once you are at temperature. Our hot end for the pellet drive is up to ABS temp in around 1 minute using our specially designed flex heater that is specifically created for this application.

If you look at the output from this current version, the flow is ample for printing and it is very efficient in both cost and power.

I do appreciate the feedback and the support (please accept the above more or less as just factual rebuttle, rather than an irritated rant). I think we got side tracked by following something that is more similar to how things are done in the industry with a large melted mass, but really we should be looking at the printing hot ends instead and equipment like a hot glue gun or soldering iron for the finesse our application requires

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