Hacking the DF64 exit chute - Page 12

Grinders are one of the keys to exceptional espresso. Discuss them here.
haematit3

#111: Post by haematit3 »

Thanks Jaybee. Will do the same. :)

CrazyBlue

#112: Post by CrazyBlue »

GDM528 wrote:The 25-degree downspout is for people that have a 10-degree base tilt under their grinder.

The expansion chamber was designed to fit into a portafilter, but the grind will pile up way too tall. Some sort of dosing funnel seems essential to contain the grind.

I haven't looked to see if there's some study of the distribution of fines as the grind proceeds, but someone did study the optimum distribution of grind size in the puck: https://medium.com/overthinking-life/st ... 0b68144f94
Wow, very interesting thanks for the link. Yeah so far it is anecdotal, based on comments of people in reddit, youtube etc, that that they found better shot quality after they started dosing direct. I'll try out your print and report back once it's all here.

Not sure why FDM seems more expensive. Is it because the material is ABS instead of the usual home-use PLA? (That site costs $4 for the expansion chute with FDM/ABS and $1 for SLA resin for the expansion chamber, just as a comparison.) To be honest it's my absolute first time looking at these materials and to think I'm in here because of an espresso hobby... hahah :lol:

Also thanks for your response on the other parts of the question!

GDM528 (original poster)

#113: Post by GDM528 (original poster) »

CrazyBlue wrote:Not sure why FDM seems more expensive. Is it because the material is ABS instead of the usual home-use PLA? (That site costs $4 for the expansion chute with FDM/ABS and $1 for SLA resin for the expansion chamber, just as a comparison.)
I don't think there's a significant cost difference between ABS, PLA, PETG, etc. for basic printing filament. I bet print time, setup, and handling labor are the primary cost factors, and JLPCB has figured out how to get really efficient with SLA printing. PLA is easier to work with, which is why I think it's so popular for home use.

The pricing you're getting for the SLA prints is less than what it costs me to print at home - at least my shipping is free and instantaneous ;)

CM00

#114: Post by CM00 »

I'm just back from the testing bench with the upgraded versions of the chute. I have been using the stock chute in combination with the Mythos declumper and I was somehow OK with the overall retention, but I couldn't ignore anymore the deposits inside the chute after 2-3 days of operation.

I am totally zero when it comes to 3D printing so I sent the "chute aperture large + 25 degrees " files (from the link above) to one of my friends who is a dentist.
He made me the chute, perfect match for the grinder, absolute spot on.
When I looked inside the chute I thought that this version will clog immediately, given the small (in my opinion) orifice and somehow choked at the exit point vs the normal diameter at the other end.
Well, I am happy to report that I was wrong, it seems that the grinds are flowing nicely into the portafilter although noticeably slower.
There is no static whatsoever and that surprises me a lot, obviously in a pleasant way!
I tested before the first version of the improved chute and the static was intolerable for my OCD, with/without declumper.
Now, I don't know whether it is the material he made the chute from or not (food safe he said) but the first 5 tests were simply amazing - clean grind, less fines, no big clumps (eureka mignon style) and most of all - no retention.

The only noticeable thing is indeed a slower grind vs the previous setup. Has anyone else noticed that?

And a big thank you for the creativity and generosity of our fellow @GDM who shared with us the secret to a better DF64.

Cheers!
cm

GDM528 (original poster)

#115: Post by GDM528 (original poster) »

CM00 wrote: it seems that the grinds are flowing nicely into the portafilter although noticeably slower.

The only noticeable thing is indeed a slower grind vs the previous setup. Has anyone else noticed that?
I printed up a copy of the larger aperture chute, and captured high frame-rate videos to compare the output streams. Each video is 1 second of real-time, captured at around 250 frames per second, then remapped to 30 frames/sec for the posted videos. I say 'around 250' because I couldn't lock the frame rate. So the original chute frame rate is 238 frames/sec and the new chute is 266 frames/sec - useful to know if you try measuring movement per frame.

I grind finely for espresso, about 10 ticks from burr-touch with the original Italmill burrs. The beans were a hybrid Full City roast with an odd grind behavior due to an admittedly bizarre home-roasted profile - that should be largely inconsequential for the purposes of this test, but hey, full disclosure. I imagine a light roast / coarser grind for pour-over would behave a lot differently, so YMMV. I also went extra-heavy with misting the beans to get the grind to clump up a bit more to make it easier to track movement in the video.

First, the original version of the exit chute:
Next, the latest larger-aperture chute:
They look pretty close to me, however, the width of the stream of grounds is wider with the larger aperture chute. If the grind rate of the burrs is the same, a wider stream would have to run slower, or be more dispersed across the wider stream, which my brain could interpret that as appearing slower, although in this case too subtle for me to pick up on. This might be more apparent at a different grind setting.

Installing the new chute requires removing the base plate, which will likely shift the burr position unless the screws are exactly tightened as before the swap. Even though I used the same beans, there was a significant difference in the flow rate of the shot I pulled - it was faster, which generally implies a coarser grind, which in turn may affect how the grind flowed through the system.

So, my observation is the flow was largely the same. I'll keep the larger aperture chute installed to monitor accumulation inside the chute. And on that point, here's what the previous chute looked like after many weeks of usage without any deep-cleaning maintenance:


The total accumulation is much less than 0.1g and was pretty firmly entrenched, such that it would take a probe/pipe cleaner/brush to remove it. I attribute some of the stickiness to the roast level of the beans I run through the grinder, as the oil from the Full City roast level may be acting as a binder, and the fine grind isn't abrasive enough to clean off the deposits. It will be interesting to see how the larger aperture version will behave...

999mor

#116: Post by 999mor »

Just wanted to say to anyone how considering this upgrade.

AWSOME UPGRADE! HIGHLY RECOMMENDED!

installed the larger orifice one, with the ssp hu burrs no more blockage, changing grind size to cold brew size and returned to espresso grinds still not provoking clogging.

I added small holes near the burrs to hold wires to make clump crusher. Yesterday I looked up the chute and no buildup was visible.

But I'm not using the down spout with the expansion chamber because of the stepnthere is between those parts. Printed new one combined and a bit modified to suit my different than original cup, still tinkering it.

Many thanks for your work, its awesome and working great

ltanzil

#117: Post by ltanzil »

spopinski wrote:Nice find! I also lives in Indonesia and very intrigued :D
for indonesian user :D

https://tokopedia.link/Iy4bGIWqmrb

back to chute again. does metal chute help with the static? i saw some one made a metal one. but i cannot tell whether it help with retention or static?

User avatar
Jeff
Team HB

#118: Post by Jeff »

Moderator's note: VFD-related discussion split to Controlling the RPM of a DF64 with a VFD

GDM528 (original poster)

#119: Post by GDM528 (original poster) »

ltanzil wrote:back to chute again. does metal chute help with the static? i saw some one made a metal one. but i cannot tell whether it help with retention or static?
I and others have tried metal exit chutes - I even tried a metal chute feeding into a portafilter charged to 3,000 volts, to electrostatically attract the grounds. I didn't find any real benefit, and have some theories why:

1) The grounds are in the exit chute for less than 1/10th of a second, which doesn't afford much time to dissipate charge. I think that's one of the benefits to the original factory clump crusher: it stalls the grounds in the metal grind chamber so they have more time to discharge before heading down the chute - but that's in exchange for the grounds being smashed by the three impeller blades in the chamber. I could argue that removing the clump crusher will produce grounds that are more reflective of the snazzy burr set upgrade you invested in.

2) Only a small fraction of the grounds actually come in direct contact with the surfaces inside the exit chute, which is necessary to quickly dissipate charge.

So I gave up on solving the static issue inside the grinder, and focused on reducing grind damage, ultra-low retention and ultra-low carryover. I gather that not everyone is using the downspout and expansion chamber, but that's how I manage the static issues: with containment.

ltanzil

#120: Post by ltanzil »

GDM528 wrote:
So I gave up on solving the static issue inside the grinder, and focused on reducing grind damage, ultra-low retention and ultra-low carryover. I gather that not everyone is using the downspout and expansion chamber, but that's how I manage the static issues: with containment.
thank you for the insight. i will put attention on those as well. right now i use mythos style declumper. i saw in previous post some use acupuncture needles as clump crusher. does it work or go without declumper all together. what has better result? i dont mind doing more puck prep such as WDT.