posts tagged with the keyword ‘inkscape’

2018.05.02

wire-bender-1894

We’ve got a project at Brinn Labs where we need to bend some 16 gauge wire. The wire bends very easily, in fact, too easily, and you can bend it by hand, but you can’t really get nice curves. I looked up “wire benders” and found “fret benders” which people use to curve the frets for guitar building.

wire-bender-plan

So I found this video titled DIY FRET BENDER – $5 USD FRET BENDER and I was in such a hurry I didn’t even realize the guy provided a bunch of design files! I guess I just often assume people don’t supply files, so I took a screen shot of the design and then dropped it into Inkscape and…

wire-bender-2d

I just whipped up my own design quickly. Since I didn’t want to screw around with using the CNC machine for this, I just exported the DXF and extruded it in OpenSCAD so I could create an STL file suitable for 3D printing. Since there’s a slot and not just holes, it’s not the most fun thing to make with a drill press. Typically slots require a bit more work than holes, with filing and other time consuming hand tool work that is often best left to machines…

wire-bender-render

I designed three parts, and then printed the body and three spacers and six guides. You’ll notice a small lip on the guide piece. That’s to just touch the inside of the bearing so they can roll smoothly. The bearings? Yeah, tear apart that fidget spinner! We’ll need three bearings.

wire-bender-1893

We’ll also need three 5/16″ bolts and nuts, though you could certainly use 8mm if you’ve got those handy. Hey, look, we’ve now got a wire bender!

wire-bender-1901

There’s a little room for improvement on this version… The slot could be a little narrower, and I’ve found that without pliers it’s a bit difficult to tighten the nut. I fixed that by 3D printing some nut knobs so it can easily be tightened by hand. (I already had my own nut knob design file, but you can find plenty on Thingiverse and Youmagine.) No photo because I added it later. :/

wire-bender-1898

This was a really simple build, and since fret benders often cost $50 to $100 (though I saw one for $25 on eBay) this was pretty dirt cheap. I don’t know if it’s up to the task of bending frets, but it should work fine for the wires we need to bend.

wire-bender-1911

If I get around to it I’ll clean up the files and release them. You never know when you might need to bend some wire!

2018.04.29

lc014

I’ve been using LaserCut 5.3 to control a G.Weike LC1390N Laser Cutter, and since I use Inkscape to create my files, I thought I’d go over a few of the settings I use so that in the future when I forget I can read this post.

I won’t go too deep into using Inkscape for laser cutting, as it’s a topic I’ve covered before, and besides having to use DXF files instead of PDF files, nothing else has really changed.

lc000-inkscape

In the image above you’ll see a file being exported from Inkscape as a DXF file for a “Desktop Cutting Plotter” which, I guess, is one way to describe a laser cutter. :) I’ve avoided selecting the ROBOMASTER option, as that does strange things to DXF files. I’ve also avoided the LWPOLYLINE option. While the LWPOLYLINE option sometimes works, it sometimes causes issues. Don’t select either option when outputting from Inkscape to import into LaserCut 5.3.

I create my files using millimeters for units, and then export the DXF with pixels (px) specified. I believe there is still a bug in Inkscape that will screw things up if you choose millimeters for the export. (We’ll double check the imported size later to make sure it worked properly.) One more nice thing about Inkscape is that it’s easy to switch between millimeters and inches on the fly while drawing.

lc001

When importing the DXF file into LaserCut 5.3 it may show some weird dialog. Ignore it. Files seem to import fine even when this shows up.

lc003

Our file has imported and looks okay. You’ll notice that the lines in the file are all black, well, actually they are all red here, as they are highlighted because they are selected. (Anyway, I forgot to set colors for some objects, but we’ll touch on that later.)

lc006-scaled

After importing your file you can check the size of it using the “Size” button in the toolbar to bring up the size dialog when your object is selected. It will show the length and height (well, it calls them both “length”) and some boxes where you can type in new values.

lc007.png

Pro-tip: If you fill in one value to scale your object, you can scale it proportionately by clicking the ‘…’ button on the other value. Here I’ve typed “100″ in the x value box and then clicked the ‘…’ button on the y value box.

lc010

The other trick I’ve learned from the folks at Brown Dog Gadgets is to use the “Unite Lines” feature.

lc012

I just use the default settings it presents…

lc013

I think this combines the individual line segments that the DXF file is made up of. If you know for sure, let me know!

lc015

Here’s what I forgot to do in the above example. I’ve set specific items to specific colors in Inkscape, so that when I bring the DXF file into LaserCut 5.3 I can use the colors to change the order of cutting operations.

lc016

Here’s our DXF file imported into LaserCut 5.3 with the colors of the lines showing. Up in the right corner you can see where LaserCut 5.3 recognizes all of the colors in the file and allows you to choose individual settings as well as the order. Typically you want to cut inside pieces first and then outside pieces.

Finally, I’ve relied heavily on the work of others, and here are some links that might prove helpful when using LaserCut 5.3 and a G.Weike laser cutter. (And yes, some of it may conflict with what I’ve posted here. Again, if I got anything wrong, please let me know.)

2017.03.31

Borrowing a bit from our friends at Bolt Depot, their chart showing US Machine Screw Diameters is helpful, but often I’m designing with Metric units (or a unit-less system that outputs in millimeters) and I need to convert Imperial units to mm. (I tend to do a lot of work using OpenSCAD and Inkscape for 3D printing.)

The chart below allows me to specify screws and bolts and then design holes that will work. For instance, I used a lot of #4 screws, and the chart tells me I need a hole diameter of approximately 2.794mm. Handy!

Size Thread Diameter
Decimal Nearest Fractional Metric
#0 0.06″ 1/16″ 1.524mm
#1 0.07″ 5/64″ 1.778mm
#2 0.08″ 3/32″ 2.032mm
#3 0.09″ 7/64″ 2.286mm
#4 0.11″ 7/64″ 2.794mm
#5 0.12″ 1/8″ 3.048mm
#6 0.13″ 9/64″ 3.302mm
#8 0.16″ 5/32″ 4.046mm
#10 0.19″ 3/16″ 4.826mm
#12 0.21″ 7/32″ 5.334mm
#14 0.24″ 1/4″ 6.096mm

See Also: Millimeters, Inches, Fraction, Decimals

2015.11.15

Sensors

I recently prototyped a device to read cards (physical cards with printing on them) for a project. I used five SparkFun Digital Line Sensor Breakout Boards attached to a 3D printed mount and wired up to an Arduino.

Card and Sensors

The cards have five blocks at the bottom, which are either black or white, representing 1 or 0. Using ones and zeroes allows us to create a binary encoding scheme, so with five positions we use 1, 2, 4, 8, 16 for the values and can represent any number from 1 to 31.

Sensor Mount

I started by grabbing the image of the sensors from the SparkFun product page and dropping them into Inkscape (sized appropriately) so I could design the barcode part of the card, and so I could design the mount for the sensors.

Sensor Mount

Once I had a 2D design in Inkscape I exported it as a DXF file and used the linear_extrude command in OpenSCAD to create a 3mm tall plate, and then added another plate. It wasn’t perfect, but it was fast. I started the 3D printer while I got to work soldering…

Sensors

Sensors

Sensors all soldered up, mounted to the plate with 3mm screws, and wired to an Arduino via a breadboard. All of this is still prototyping stage. It doesn’t look pretty, but it worked and it was enough to test things out and do a demo.

Cards with Barcodes

Here’s an example of some card templates. Can you determine what number is being passed by reading it in binary? Since we’ve got 5 positions we can have 31 different cards… If you needed 63 cards, you would need 6 positions (and one more sensor.) 127 cards? That would be 7 positions and two more sensors. Any more than that and you might consider using the SparkFun Line Follower Array which has 8 sensors on a single board.

Card and Sensors

The total time to create this prototype was just a few hours from starting a design in Inkscape to 3D printing a piece, soldering up and mounting the sensors, and writing the code. (I also wrote a simple Processing application which read the serial output from the Arduino to display the card data on screen.)

2015.08.26

Make

I wanted to document how I did the artwork and toolpaths for the MAKE thing I make on the Shapeoko CNC router at BAMspace recently…

Make

I started with my old MAKE design in Inkscape and set it to the size I wanted. I also placed it on the canvas as if it were on the piece of stock, knowing that the lower left corner would be the home position on the CNC router.

Make

After I saved out my SVG file, I loaded it into MakerCam. Now, you can go to www.makercam.com and use that, or you can load up the SWF, and save it locally to run on your own machine. (Flash is required either way. I guess the source code is also available, but you probably need Adobe’s Flash development tools to do anything with it.)

If you’re using Inkscape, you need to set the prefs to 90ppi instead of 72ppi before you open your SVG file. Oh, make sure you check out the MakerCam tutorial, help, and about pages.

Make

In MakerCam I created two profiles, one to cut the inside pieces, and one to cut the outside of the entire piece.

Make

These setting worked fairly well. I would up the feedrate or the step down on our machine if using 1/2″ HDPE. This job definitely took a while to run…

Make

Once I had the toolpaths all set in MakerCam I exported the G-Code into a single file, and then loaded that file into OpenSCAM to run a simulation. (Looks like OpenSCAM recently rebranded as CAMotics… guess I should grab the latest version!) Running the simulation allows you to see the toolpaths and check how many passes it will take to cut through the material. I guess you could also use math, but sometimes I prefer visualizations…

That’s pretty much my workflow for 2.5D toolpaths; create art in Inkscape, load it into MakerCam and generate G-Code, load G-Code into OpenSCAM (CAMotics) and see how it looks.

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