I'd mentioned in my Webster build thread that I had recently purchased a hobby class die cutting machine for making engine gaskets. I'd made plenty of gaskets in the past but for these small engines, my efforts were pretty sloppy and poor. I'd started looking at these types of machines for some time and then one of the local hobby/craft stores had a sale and I picked on up. I'll try to detail why I picked the machine I did and then will go through the basic process of creating gaskets.
The machine.
I selected a Silhouette Portrait 3 machine. See
https://www.silhouetteamerica.com/featured-product/portrait for more info on this particular machine.
This is about the smallest 'full-featured' hobby level die cutter that I could find. There are 2 main manufacturers of these sorts of hobby level machine, Silhouette and Cricut. Both companies have their fans and it seems to be a bit like automobile fans, some just like one brand over the other. I chose this machine primarily due to 2 factors: 1) The price was about as low as it gets for a fully featured machine and 2) The Silhouette Studio (SS) software is vastly better than the Cricut software. The SS software installs conventionally and has no dependency on online access to the manufacturer. Plus its quite full featured and you could probably do simple gasket designs without any external CAD software. The Cricut software is much, much more simple but seems to require a connection to the manufacturer in order to import and product a usable file to be sent to the machine.
The main limitation of the machine I purchased is that the maximum width of material is 8" although the length can be essentially unlimited. Other models in the Silhouette line go up to 24" material width. The machine I purchased cost $179 for a local store and their largest machine is about $500. The basic edition of Silhouette Studio is included with the machine. Note that I did not consider any of the larger commercial machines. These are wayyyy more expensive and are complete overkill for what I need. Most of the large commercial machines are used for vinyl signage.
Here's my machine setup and ready to go. The interface to the machine is by either USB or Bluetooth. I've only used USB so far. The material to be cut is placed on top of the plastic mat and is positioned for loading as shown. There are guides and a simple 'load' button that advanced the mat so that it's gripped by the machine's drive rollers. The supplied mat is tacky enough that teflon sheet sticks to it with no problem. The mat though should be considered a consumable as in time, it will become scarred up and will lose its adhesion. The cutter assembly is easily installed/replaced and the supplied cutter is capable of 1mm thick material. For this model, cutters can be purchased that are supposed to be able to cut up to 2mm. Other machines can go up to 3mm with high cutting pressure.
I'll go through the process I use to actually make gaskets. There are 2 methods that I've worked out and I'll go thru them in order. The first method involves producing a dxf file of your gasket and then importing it into SS for sizing and cutting. I'll note here that the basic free edition of SS can import dxf files, but not pdf or svg files. I went ahead and purchased the upgrade to a more advanced edition called 'Designer Edition'. I got it mostly because it can import pdf files (which has some advantages) and it also has quite a few more advanced drawing/modification tools. The list price for the upgrade is $50, but I purchased it from a vendor for $30.
I use Fusion 360 for 3d modeling and producing 2d drawings so my comments and screenshots are based on that. I think most CAD packages can do exactly the same thing as F360 though. You'll just have to modify your workflow to reflect how your package works.
The first thing to do is to design your gasket. Sometimes I make 3D models of the gaskets as I go along, and other times, I produce a simple model with just the gaskets. In this case, I'm showing only a single gasket. In F360, the dxf export is done from a sketch in the 3d Design workspace. Here I've made a sketch that in turn is extruded to make the 3d model. I'm simply right clicking on the sketch and then left clicking on 'Save as DXF'.
Then I open the SS software and simply 'open' the dxf file I just created. There's no specific import function needed. You can see that it comes in at the incorrect size. And all the elements of the dxf file are separate at this point.
The first thing that must be done is to 'group' all the elements related to the gasket. Here I've selected everything and then clicked on the 'group' command.
Then the gasket has to be resized to the correct dimensions, so that means you'll have to know at least one dimension from your gasket. Note here that I've clicked the 'lock' symbol to make x and y resize together and made x 1.000". The cutter will cut exactly to the sizes that you specify.
Then to actually send the file to the cutter, you go to the 'Send' screen and setup the various cutting parameters such as blade depth, cut pressure, material, etc. Also you need to make sure that what you want to cut is shown with the heavy red outline. Normally thicker, heavier materials will take multiple passes which are specified on this screen. Experimentation and trials are required!
Next I'll show the process using a pdf file. I prefer this approach as the pdf file, when imported into SS, comes in exactly at the correct size and is grouped properly. The ability to do this is the main reason that I paid $30 for the upgraded software.
The process is started in F360 Drawings. Shown is a basic drawing with no dimensions applied.
Then since everything on a drawing is exported when making the pdf, I've found that it's easiest to clean things up now. Note that I've deleted all drawing features so that the pdf only contains the gasket, no legend, no dimensions, no guidelines, nada.
To import the pdf, simply 'open' it in SS. Note that you must choose the 'import as vector' option vs the 'image' option. This couldn't be easier.
Note that with the pdf import, the image comes in grouped and is at the proper size. It can now be sent to the cutter. I didn't illustrate it, but when I cut the actual gaskets for my Webster, I created a drawing with the 4 gaskets I needed and imported them as one pdf. That way I could cut all of them at one time. If you need more than one gasket of the same type, it's also quite easy to duplicate an image in SS so as to make multiple copies as needed prior to sending to the cutter.
And finally, here are the various gaskets that I cut for my Webster project. I cut way more than I needed as I was experimenting with different materials. Shown here are gaskets cut from the following material: 1/64 Felpro fiber paper, 1/32 Felpro fiber paper, .005 sheet teflon, and .010 sheet teflon. I tried to cut some .030 teflon sheet that I had but I was not successful. The cutter simply wouldn't penetrate all the way through that material. I do want to try a different cutter assembly but I've not ordered it yet.
That about sums it up! I'm extremely happy with the way this machine works for making small, delicate gaskets. The gaskets are exactly to size and any curved areas are completely smooth. Also this setup is capable of cutting quite small holes with great precision and accuracy. I look forward to using on more projects going forward!
If anyone has any questions, I'll be glad to try to answer them.
FYI.
MIke
