I like simplicity, both in nature and in programming. So in my opinion, CAM programs either work well from the beginning or they steadily die away. That is why I will be writing a series of articles (beginning with this one) showing how the SolidWorks program and the CAM add-ins work together to make some pretty neat things.
As a point of reference for my own experience with this software, I work out of a 17' x 30' lab with a Laguna Swift CNC Router and an Epilog 120 watt CNC Laser (see picture).
Now let's get started. Simply put, CAM programs tell CNC machines how to subtract or take away material from a piece of stock, producing the CAD part specified in your design program. It is a complicated concept for sure, but a simple enough process thanks to certain user-friendly programs.
SolidWorks is my preferred Mechanical Computer Aided Design program (MCAD) – and I am pretty familiar with HSMWorks, which was recently bought by the Autodesk Company and is shown in the second image embedded into SolidWorks. I should note, though, that all my work was done through the FREE Xpress Version of the program, which you can find at the HSMWorks website.
I think it's important for MCAD users to learn CAM programing. After all, what good is any CAD design that you cannot build with a CNC machining operation? Learning how to build or produce a part will make you more conscientious of that – and it will show in your future work. Even if you never produce a final product, you will at least be able to see in the simulations how things are done in machine shops.
In reference to the screenshot, the Command Manager shows the tools that can be clicked on to initiate work, while the extreme left hand column is the HSMXpress history tree that contains the steps in their proper sequence. The yellowish colored box surrounding the small plaque is the bounding box. And in case you were wondering, the plaque is one I am making for Mr. John Hayes as a thank you for allowing me to share my thoughts and experiences with all of you on ENGINEERING.com.
CAM is growing in leaps and bounds. There are many free video tutorials on web sites to walk you through designing simple parts for machining; which is a great way to learn the basics, though I find you need to watch each video at least a few times.
You can also run simulations of your part being made right inside of the program. You do not need to run another program or have multiple viewing screens. Everything you need is right there inside of SolidWorks or Inventor.
Next, I will show some screen shots of the simulations I ran and used to optimize my toolpaths, all because I could see exactly how my programming was going to make that part.
In our shop, we generally use screws to fasten the stock down to the "sacrificial board" on top of the metal cutting table. Since we are not cutting large metal parts, we do not have the stresses that would normally be found in a metal machining operation, which would likely require large clamps or machine vises.
We are also not in a production environment here, but with HSMWorks the full program will do anything you might need, so make sure you check it out. HSMXpress is a fully-licensed free version that permits you to make and sell parts, but as you might expect it has its own limitations.
In the next image are all the toolpaths shown for this job. Simulation controls are on the left hand side of the SolidWorks screen. You have many controls here that will show you all those things you want to see in your simulations.
Here is that same screen showing the first step I used, which is known as a facing operation. I removed the first 1/16 of an inch off of the 1/2-inch stock material to get rid of all the blemishes, stains and surface roughness originally present in this scrap redwood. Needless to say, it started off pretty ugly.
Here my simulation is showing the inside pocket being carved out using a half inch flat end mill.
A little more progress with that pocket being made is shown in the next image. All those dark lines are toolpaths and they show the movements that were used to make each feature I designed in SolidWorks. It is also fully parametric, so if you make changes to one program both programs will update – though a rebuild is required.
Here we have the first outer contour being made. The screws that I placed to hold this piece down on the cutting table's "sacrificial board" were placed in the corners of the Green Stock Material. I counter sunk them enough to ensure that our router bit would not come in contact with them.
Once again, I removed all the toolpath lines to show you the letters that are being cut out or engraved here. I did the lettering with a 1/16-inch ball nose bit. It is the smallest bit we have in the workshop.
The final contour cut has been done now. To prevent the part from being cut out completely from the stock, which might damage it, I told HSMXpress to leave 1/32 of an inch of material at the bottom that would hold it in place. Then I backed out the four screws from the corners in the green, counter sunk holes and cut the rest out with a razor knife. Finally, a very light sanding removed all the thin material from the plaque.
I finished with two coats of pure boiled linseed oil as a preservative, and with the plaque baking out in the strong Las Vegas winter sunlight it soaked it all up just like a sponge.
As you can see below, the final result is simple, elegant and very well constructed. It is meant to serve as a coffee cup coaster to stop drinks from marring up the CEO's desk! I should also mention that in the HSMXpress version you can nest the parts to be made so you can make a whole bunch of them.
In my next article I will show you some more items we made using the HSMXpress CAM program. Oh, and for all the Inventor users out there, your version will be the HSMExpress free version. A harmless difference in names as the functionality is mostly the same.