Koffiepraat.nl forum over koffie, espresso, filterkoffie, horeca en technieken

bobbee schreef: di 16 mei 2023, 11:22

fransg schreef:

bobbee schreef: di 16 mei 2023, 11:13Ik zoeken en zoeken, die hele pagina niet gezien! Maar ik heb hem hoor! Thanks.

waar dan URL?

In de 1e post staat de link naar hey bestand en de description pagina/tab bevat de info. Ik kan niet direct linken naar die tab op die pagina. Sorry.

Description
WDT is an art. Its chaotic nature takes a lot of skill to master.
Umikot is a Tagalog word which means: to spin; to turn around; to revolve; to rotate; to circle; to go around; to swirl; to gyrate.

In that spirit, this 3D printable tool utilizes a print-in-place planetary gear mechanism to create spirographic needle motion. It is compatible with standard, 58mm baskets. (54mm is in the works!)

This design is provided to you for free under a Creative Commons CC-BY-NC-SA license. Make and enjoy, but do not sell.

A common problem with many commercially available WDT tools is that they utilize concentric motion, which creates trenches in the coffee. The spirographic pattern avoids needles crossing the same path, with the goal of a more homogeneous particle distribution.

I have optimized the needle pattern for even coverage, and no more than 8 rotations of the handle should be necessary. Two different needle lengths provide deep and top of the bed distribution.

The needles are inserted from the top and are replaceable, and the base is swappable, allowing for configurable needle depth for different baskets, without needing to change out the needles. Optionally, you can print versions of the base that can house eight magnets and/or include a flange to interface with the portafilter lugs. A little de-bossed label to indicate a given base's depth is included for easier identification.
Instructions
Gather your parts and materials.

For the non-printed things, you will need:

5x M3 x 12mm flathead/countersunk screws
10x 0.35mm acupuncture needles with a 30mm handle (I used the same as the popular 9-prong tool, 0.35x75mm from aliexpress)
[OPTIONAL] 8x 5x3mm magnets for the each base you wish to print
Cheap flush-cutters you don't mind dedicating to needle cutting
Screw-driver/Allen-key for the M3 screws
A 3D printer

Print your parts!

I printed mine with PLA.

Settings:

0.2mm layers
4 top/bottom layers
2 walls are sufficient
11% gyroid infill is sufficient
No supports

The gears and needle holes require your printer to be well calibrated!

Printed Parts:

1x Upper Mech
1x Spin Ring
1x Handle
1x Base (see Base Options below)
1x Stand (see Stand Options below)

Base Options

The Base part is available in different versions for:

Various needle depths
With or without holes for magnets (Magnet/NoMagnet)
With or without a flange that interfaces with the portafilter lugs (Lug/NoLug)

Pick the needle depth that fits your 58mm basket. The filenames include the depth (i.e. Umikot - Base 25mm Magnet Lug.stl). See below for some common needle depths.

If you want to put the eight 5x3mm magnets in your base, be sure to print the Magnet version. Otherwise, print the NoMagnet version.

If you are going with NoMagnets, or your basket is not magnetic enough to prevent Umikot from rotating during use (I found this to be the case with an IMS basket), and you do not want to hold Umikot down with one hand while operating with the other, print the Lug version with the flange. Otherwise, print the NoLug version.

Common needle depths are:

15g basket
21mm
18g basket
23mm
20g basket
25mm
22g basket
27mm
Sworks 18-20g basket
23mm
Weber Workshops 18-22g basket
24mm
Pullman 19-20g basket
25mm

Note: For the very best fit, measure the internal depth of your basket. The above are based on specifications and have not all been tested. Please let me know if these recommendations need adjustments!
Stand Options

Print the corresponding stand, either Lug or NoLug, depending on the base you choose.
Cut the needles to size.

The designed needle depth for the various base files assumes the needle length to be cut exactly. If anything, favor slightly short.

The needles are likely harder than the cutting edges of most cheap flush cutters, so be prepared to dedicate them to the cause. I used a very inexpensive one from a multi-pack I got off of Amazon.

Be very careful to safely dispose of the cut ends of these needles!

First, cut 5 of your 10 needles to a total length of 65mm:

Cut the remaining 5 needles to a total length of 55mm:

To secure the needles in their places in the gears, give them a little bend, like in the above photo. This way they they won't rattle around, but can still be removed if they ever need to be replaced.
“Tap” the gears' screw-holes

To make our lives a bit easier later, “tap” the holes with one of your M3 screws. Carefully screw them into each of the gears' holes, stopping when you feel the resistance noticeably increase (you've hit the bottom) and then removing the screw. Repeat for each of the 4 larger gears. You will need to hold the gears carefully to keep them from rotating while you do this. Be careful you do not get pinched!
Attach your base

[Optionally, press in the magnets if you went with the Magnet version.]
Screw on your chosen base. You can change bases at any time, but be very careful when doing so when the needles are installed!
Insert the needles!

Be careful during this step - the trimmed needles are still thin and sharp! Place the assembly onto its stand at this point to keep the tips in a safe place. Gently insert each needle until it sits flush with the top of the gear. Do not force them! Give them a little jiggle if they are not quite lining up with the hole in the bottom.

See below for the needle pattern with respect to the different needle lengths:
Attach the spin ring and handle

Gently screw in 4 of the M3 screws to attach the spin ring. Over-tightening can cause binding of the mechanism - I like to tighten until the screw stops, then back out ~¼ turn.

Then, do the same for the handle:
Distribute some coffee!

And that is it! If you chose the non-magnet version, or your basket isn't very magnetic, you will need to hold Umikot down while to turn the mechanism. No more than 8 turns are necessary.

The distribution must be done with the basket in a level position - otherwise, the grounds will tend towards whichever direction the basket is tilted.

Finally, give the whole thing, Umikot and your portafilter, a gentle tap or two to settle the fluffed grounds before removing Umikot. Tamp, pull, and enjoy your espresso!

Disclaimer: not all filaments, nor the 3D-printing process, are certified food safe. Use of this tool is at your own discretion.

FrancisPavoni schreef: di 16 mei 2023, 13:01 Ik ga hem vandaag aanzetten. Morgen klaar (al er niks mis gaat...).
Kan daarna wel een serie printen voor wie wil. Gaat denk ik per zes, kan van elk onderdeel (behalve de knop) maximaal zes tegelijk printen.