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Blog for AWESOME things that Kenny made for Fab Academy

Week - 15 Wildcard Week

2018-05-19 Kenny

Assignment

  • Design and produce something with a digital fabrication process not covered in another assignment, documenting the requirements that your assignment meets, and including everything necessary to reproduce it. Possibilities include (but are not limited to) composites, textiles, biotechnology, and robotics.

Setup

  • I was inspired by the paddle to have a light core to make it robust.
  • Markdown
  • Markdown
  • Markdown
  • Markdown

Design

Fabrication

Files

Week - 09 Molding and Casting

2018-03-23 Kenny

Assignment

  • group assignment: review the safety data sheets for each of your molding and casting materials, then make and compare tests with each of them individual assignment: design a 3D mold around the stock and tooling that you’ll be using, machine it, and use it to cast parts

Acknoledgements

  • Originally I wanted to use Solidworks because they provided us with a interface to othermill, which we use here. But since I had a fellow student how was already conversant in these technologies with Fusion 360 and due to the tight time constraints, I decided to try out Fusion 360.
  • My idea is to keep the mold simple as possible. I saw how my fellow student tried to make two parted mold with burling but it snapped off and furthermore the machining time will be quite long.
  • So I decided to make a mold for a simple coin. To make a negative silicone mold, one have to mill the stock from the top and the model has to be positive.

Design

  • After installing, with “File” > “New Design” you can create a new design. I found it quite useful that everytime you save, it creates a new version in a version control software
  • Fusion supports sketches as well as primitive solids cast
  • I was alway found of the circular letters on coins. With Inkscape it was possible to align text to a path which was a circle. cast
  • It was possible to import the svg file and extrude it, but many detail was lost and Fusion crashed several times so I gave it up. cast

Setup

  • After swiftly designing the coin by extrude-cutting the center groove and simple text, you open “MODEL” > “CAM” to start preparing the model for cnc machining. cast
  • In the CAM view, first we have to create a new Setup by clicking on “Setup” > “New Setup” on the top toolbar to configure the stock. Here are some configuration I had. cast

cast

cast cast * For the rough cutting you need to select from the tool bar “3D” > “Adaptive Clearing” cast * Here are some configurations for the actuall milling and the the roughness/passes of the clearing. cast cast cast

  • We need to configure and specify the tools we will be using. cast cast cast

  • After configuring the tool we can see some preview passes: cast cast cast

  • For the fine cutting we select from “3D” > “Contour” and here are some parameters: cast

cast cast cast cast cast

  • To simulate the whole process, we need to specify the tool head of the mill to find out whether there are collisions with the stock. cast cast cast cast cast cast

  • After successfully simulating (no red signs) we can go to “Postprocess” to export g-code for the Mill. cast cast cast

Fabrication

  • Rough cutting cast
  • Fine cutting cast
  • To clear out all the remaining wax from the cracks, I used compressed air. cast
  • I could have milled the outside boundary to pour in the silicone, but it would have required bigger chung of wax and more time, so I taped some paper onto the wax with a rubber band. cast
  • But the silicone was already hardened because we did not use it for 3 years, so for a quick fix we used epoxy and silicone for seams, which unfortunately was not dry engough and was partly destroyed. cast cast cast cast cast

Files

Week - 07 Computer-Controlled Machining

2018-03-14 Video CNC Kenny

Assignment: Make something big

Hero Shots

  • Standing Stool
  • Standing Stool
  • Standing Stool
  • Robot Platform Base

How I made the files:

  • I originally had two idas for machining: The modular shelf from Press-fit design week, the moving-basis for my final project.
  • P
  • Modular pressfit shelf
  • Modular pressfit shelf

  • Both designes were generated with OpenSCAD

  • Modular pressfit shelf

  • Base

  • And initially I hoped to be able to make carved pockets like this:

  • Modular pressfit shelf

  • But it turned out that I only had a 6mm flat end upcut mill availabe:

  • Modular pressfit shelf

  • But after a while I realized that I kinda missed the assignment to show my understanding of the topic of milling, so I prototyped a stool for the standing working station, hence everyone is using the back of a chair to sit on.

  • Modular pressfit shelf

Setup, Problem, Fixes

  • using fixings, testing joints, adjusting feeds and speeds, depth of cut etc)

    Setup

  • I tried two different setups:

    Windows: Estlcam & Universal Gcode Sender
  • In Estlcam I configured the thickness of the pocket and hence I was using two plates which will be glued afterwards, I could save time by cutting out only one board:

  • Pocket Depth

  • Two boards

  • For other parts the full depth was selected. Estlcam distinguishes between cutout and drilling and so for the four corner holes to drilling:

  • Modular pressfit shelf

  • Modular pressfit shelf

  • Here is a detailed view of the milling tool config:

  • Modular pressfit shelf

  • A detailed view of the universal gcode sender, which takes the .nc-files generated by Estlcam and sends it to the final cnc-mill:

  • Modular pressfit shelf

  • Modular pressfit shelf

  • Don’t forget to put a sacrificial layer of scrapwood into your mill. After milling too deeply, I ended up using double sacrifical layers.

  • After everything was loaded the machine’s zero position is required to be set. This is done on the one hand in the file by estlcam and then in the physical world.

  • Software zero

  • Connecting Machine

  • Z-Axis calibration

  • z

  • This is how the path looks, before something can go wrong. Afterwards, this function turned out to be more useful than you originally think:

  • Gcode visualizer

  • Neil suggested wood screws but since our bed is made out of aluminum, there have been an invention in our lab to hold it down with 3d printed parts, which are actually quite useful. Be careful not to suck them in when you are vacuuming the workspace.

  • clamp

  • Be sure to be in near of the emergency button:

  • emergency

Easel
  • Easel is a freemium web tool which is cable of doing gcode generating and sending.
  • First you have to set up your machine. Since you cannot enter precise machine dimensions, I took 75cm by 75cm since our CNC machine is capable of doing 55cm by 35cm.
  • base
  • You are able to select between outline and pockets.
  • outline
  • To enable dogbones, you first import your svg-file and select the path and go to apps and then select Dogbone Generator:
  • dogbone
  • dogbone 2
  • To configurate feed rate etc. click “cut settings” and type in your config:
  • In my case: (1300 mm/min) / (29000 rpm x 2) = 0,0224… which is quite high but an experienced member told me it is acceptable for the router-tool we are using for it.
  • cut settings
  • At the top right corner you can start the milling process. It walks you through all the necessary steps, which is quite intuitive.
  • After configurating and zero-ing the tool head, you can start milling.

Problems & Fixes

  • I accidentally milled to far, because the deapth per pass configuration is a bit strange, it was only doing 2mm althogh I tried out 1mm. I found it best, to try milling only one layer first, and then go deeper in further steps.
  • Since we only had upcut- mill, one side of the flexure turned out to be quite ugly:
  • cut settings
  • I did not think through fully the flexure constraints so I had to cut it with a eletrical saw:
  • cut settings
  • Before:
  • cut settings
  • After:
  • cut settings
  • First I tried using the gcode sender from Chrome webshop, because I was using mac but it failed.

Testing the mill

  • I wanted to know the tolerance of thickness for press-fit, so designed the testfile [here]()
  • pressfit

Files:

Week - 06 Electronics Design

2018-03-01 Kenny

Assignment

  • redraw the echo hello-world board,
  • add (at least) a button and LED (with current-limiting resistor)
  • check the design rules, make it, and test it
  • extra credit: measure its operation
  • extra extra credit: simulate its operation

Research & Acknoledgemnts

Setup

  • Originally I wanted to use CircuitWorks (Altium incorporated in Solidworks environment) but due to local hardware constraints (No powerful enough windows machine, which I borrowed from my university) I decided to use Eagle .
  • Although I tried KiCad, I found Eagle to be more intuitive.
  • Eagle provides a free version which is provided for Windows and Mac.
  • One does start a Project by “File” > “New” > “Project”. On the left side there will be a File-Manager where you can type in the name of the new Project. With right clicking the mouse on the project a menu pops up. “New” > “Schematic” you can create an empty schematic file.
  • After installing there will be a “Library” directory which you have to find out. To which you copy the fab-library Link. The library contains layout of footprints and annotation for each component.
  • Then when ever you want to use a standard component from FabLabs, you can go to “Edit” > “Add” and there will be a dialogue where you can type in fab and you can find all the components you need. Double click and and you can insert the component into a scematic.

Design

  • To create the schematic is the easy part. You keep adding the required component. Connect them with “Draw” > “Wire” option. At this step it was crutial to move the parts a little bit to see whether they are indeed connected, because I had many failed attempts where I thought it were connected, when it was not.
  • ele
  • While designing, using VCC and GND symbols are recommended for the sake of better overview but it is not crutial, since when creating the layout all the “redundant” connections can be ignored, which I found out later on.
  • ele
  • To create Board, select from menu “File” > “Change to board” and it will give you a nest of components on a dark background. You can mark them via Group-Selection from the left tool bar and right click somewhere in the void where “Move” will apper and you can move all the parts at once in the area.
  • ele
  • It is recommended to roughly place the whole nest on the lower left corner since the outline of the board (the resizable white rectangle) has its origin there.
  • Since not all PCB mills can do double sided milling (reorienting the other side is somethimes troublesome) you should keep in mind not to use vias or the back-side in this context. If you are fully aware of that and your mill supports it well, like on the Othermill, then feel free to make use of them.
  • ele
  • Now to the “fun” part. You can rotate a part with the combination “Ctrl” + “left click” on the center of the part (there is a cross on that). You try keep rotating the parts until you minimized the amount of intersecting yellow wires. Of course you can move a part to minimize the number as well with the “Move” tool from the left tool bar.
  • ele
  • This minimizing step is crutial for the actual routing with the “Route” tool. It is similar to the schematic designing, but this time the “wires” or “route” is final. What you see is what you get.
  • At first, I was eager to compleately to “find out” the route design on my own, which I archieved, but it looked quite ugly. After some iteration I just looked at the design of neil and added my twist to it. Specificly, he had a route where three routes were routed through the ATttiny pins which in my case even though pressing shift for turing off the rough rastering of the routes looked impossible to mill. So I hade to route it around the whole circuit but it worked out quite fine.
  • ele
  • ele
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  • Final:
  • ele
  • To confirm that the final routing is compliant with the final width of the traces it is useful to do “Tools” > “Verify Layout (DRC)”. And if it runs without problem, which was in my case.
  • ele
  • ele
  • To move it as group:
  • ele
  • There are two ways of exporting. If you are using mods, you want an image, but if you are using other CAM (in my case Bantam Tools) then you can just save it and import the brd file into it.
  • To prepare your design for exporting image, we need to seperate between the outlines of the board and the traces. This can be archieved by (de)selecting “View” > “Layout preferences” and for the outline obviously “outline” and for the traces you want to activate “Top” and “Pads”. When you have selected either of the configuration, you can go to “File” > “Export” > “Image”. Here is examplar configuration.
  • ele
  • ele

Fabrication

  • Hence I wanted to try how I could only use the Bantam Tools to make the PCB I sticked to the simplest configuration.
  • ele
  • Furthermore I wanted to tryout using a engraving bit (which is more robust and cheaper than very fine mills which can break easily). After configurating the tool in the software, as usual I measured the thickness of the board and started milling, but the tip of the engraving bit was so fine, it did not reach the board. Manually testing the deapth 0.1mm offset was necessary to have viable results.
  • ele
  • ele
  • ele
  • Like the electronics production week I gathered the necessary components before assembling. I found it useful to hold the pcb with a “third hand”.
  • ele
  • ele

Measure it’s operation

  • Voltage, Signal

Problem & Fixes

  • not so far

Files

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