Week 17 - Applications and Implications & Project Development

This week we have the following tasks to complete:

Propose a final project masterpiece that integrates the range of units covered
- What will it do?
- Who's done what beforehand?
- What will you design?
- What materials and components will be used?
- Where will come from?
- How much will they cost?
- What parts and systems will be made?
- What processes will be used?
- What questions need to be answered?
- How will it be evaluated?
Your project should incorporate:
- 2D and 3D design,
- additive and subtractive fabrication processes
- electronics design and production
- embedded microcontroller interfacing and programming
- system integration and packaging

What will it do?

The goal of the final project is to design and produce a smart filament drying box, which core feature is to weigh the filament that is left on a spool. This is necessary because of the long way between the direct extruder and the spool it takes a lot of time to unload the filament to make sure that enough is left. Some materials like TPU and PETG could absorb moisture from the environment which results in bad prints. To counter this project the box will have some passive and if the time allows it some active drying capabilities, realized by using silica pearls and dehumidifier membranes. The box will display the remaining filament on a displays and with the help of Neopixels.

Who's done what beforehand?

A filament drying box for the prusa xl got already designed by Surfalex2000 and can be found on Printables. A filament scale was for example already designed and sold by creality. An open source version was designed by moXDesign.

What will you design?

I'll design the filament holder with scale integration and the integration into a typical eurobox. The user interface will also be designed by myself. The different subassemblies that I design myself will be found on the final project page.

What materials and components will be used?

The base material for the production will be PMMA for the internal structure of plate shapes. More complex geometries on the inside will be in the first iteration out of PLA later out of resin (printed or casted). Components around the drying membranes will be from the same material. Outside housing for the user interface will be resin printed for the front side and the knob and PETG or ASA for the backside for fast and easy production and a high lifetime. PCB's will be out of FR4 because of there heat resistance and the easier solder workflow even with all the consequences and caution that needs to be applied while machining. Screws will be mostly based on DIN EN ISO 10642 and ISO 7380 without flange with hexagon socket. Electronics will be consists out of XIAO ESP32-C3, OLED Display, Rotary Encoder, ADC and Adafruit Loadcells. More details for everything with amount, links and prices will be found in the BOM on the final project page.

Where will they come from?

The eurobox is produced in Bavaria, Germany, the electronic components are produced in China, Taiwan and probably Korea. The loadcells and Neopixels came from New York, USA. The screws are made in WIP. The acrylic came from WIP and the filament is produced in Czech Republic and the resin came from Germany, USA or China.
The Eurobox, OLED-Display, HX711 Modules, Loadcells, Dehumidifier Membrane and all electronic components that are used on a pcb will be bought, everything else is designed and produced by myself or in case of the code I'll receive some help from an AI.

How much will they cost?

The exact price may be variable based on location and supply chain. In my case I looked that everything is available at a minimum of different amount of suppliers. In my case the project cost around WIP on material. Machine and work time not included.

What parts and systems will be made?

The spool holder, silica pearl compartment, inner structural parts, all pcb's that are not included with a module (display, ESP32 or HX711), a knob for the rotary encoder and component housings will be made.

What processes will be used?

For structural parts laser cutting and for the first iteration FFF printing, later SLA printing or casting will be used. PCB's will be milled and after that hand soldered.

What questions need to be answered?

How much power do this project need?
What power supply will be used?
What will be the structure of the menu?
What process will be used to produce the distribution pcb?
What drying module will be used and controlled?
How to use multiple HX711?

How will it be evaluated?

Can the project weight a filament spool?
Can it show how much filament is left on the spool?
Optional: Does it keep the inside dryer that the outside environment?

What tasks are completed?

✅ First complete CAD model
✅ Spoolholder production and test
✅ Loadcell integration
✅ Main PCB design
✅ Main PCB production

What tasks remain?

❌ Firmware programming
❌ User Interface housing final design
❌ User Interface housing production
❌ Menu design
❌ remaining spoolholder production
❌ active drying module design
❌ active drying module production
❌ video production
❌ presentation

What will happen when?

If something is not working I will reduce the overall features to the first spiral that I describe in week 15. If encounter problems with the distributionplate I'll use cables to connect everything together. Most of the critical features are already checked in other weeks like the input devices in week 9 and output devices in week 10. If some problems occur with the production of 2 sided pcb's I redesign the main board or split it up in 2 boards that I sandwiched to get a "two sided pcb".

What has worked? What didn't?

In the moment I'm a little bit behind with my progress but it is still enough time to finish a one spool scale solution with all spool scales still in reach.

What I Learned This Week?

A regular verification of the progress is necessary and makes it easier to plan the next steps.
Side tasks need more time then calculated. A better overview could help to improve the time situation.

What I want to improve next week

A general better overview over all remaining tasks and specially the tasks outside of FabAcademy that I have to do.

To create this page, I used ChatGPT to check my syntax and grammar.

Source code hosted at gitlab.fabcloud.org