FreeCAD News

The author of this blog is quite inter­est­ed in design­ing and build­ing open source machines and tools. Recent­ly a, designed in FreeCAD, 4 axis CNC hot wire foam cut­ter has been a great project. It’s fab­u­lous that not only can we design such a machine in FreeCAD, but also FreeCAD, via the Foam­Cut work­bench, pro­vides a way to cre­ate g‑code files to cut out foam parts. Of course, we can also design those parts in FreeCAD, Perfect!

Often used for cut­ting wing sec­tions and oth­er com­po­nents there are a lot of appli­ca­tions for RC plane builders to design and cre­ate g‑code for wings. The Foam­Cut work­bench enables a much wider vari­ety of parts to to be able to be cut. It is avail­able via the Addon man­ag­er, it’s also worth read­ing through the notes in the addon man­ag­er list­ing, or direct­ly on the Github repos­i­to­ry as they pro­vide a great overview of the includ­ed tools, oper­a­tions and procedures. 

The work­bench­es pri­ma­ry devel­op­er is Andrew Shko­lik but is found­ed in the work of Andrei Beborodov who cre­at­ed and shared a set of macro’s for cre­at­ing foam cut­ter g‑codes in the FreeCAD community.

Once installed the work­flow is laid out in a rea­son­able and straight­for­ward struc­ture. With a tar­get part cre­at­ed you move to the Foam­Cut work­bench. High­light­ing the part in the mod­el tree and then click­ing the first Foam­Cut wb icon “Init machine” ini­tialis­es a machine and a job. You can use the Con­fig ele­ment to match the machine para­me­ters, the axis labels, the wire length, the axis dimen­sions etc to your real world machine. You can also do this via the tools _edit para­me­ters drop down menu find­ing the Work­bench sec­tion with the Foam­Cut work­bench machine con­fig­u­ra­tion set­tings. Here you can add these details which will become the default each time you ini­tialise the machine mak­ing it match your real world set up perfectly. 

You can then either use the “Cre­ate path” tool or the “Cre­ate Pro­jec­tion” tool to cre­ate paths on the side work­ing plane of the emu­lat­ed machine from select­ed faces or edges of your part. The pro­jec­tion tool cre­ates the same sym­met­ric paths on each side of the machine essen­tial­ly makes a dou­bled 2 axis oper­a­tion where each side of your machine will be mov­ing along the same paths. The Path tool can be used in this way, but also allows for true 4 axis oper­a­tion where you are mak­ing some form of taper­ing part.

You can then select paths, or ver­tices on the pro­ject­ed ele­ments and add entry or exit paths for your hot wire to fol­low. In turn you then mul­ti select the paths in the pre­view win­dow in the order and direc­tion you want the wire to fol­low. So this would usu­al­ly begin with the “Entry Path” then per­haps, path, path001, path002, path002 etc and then the “Exit Path”. With the paths select­ed in the cor­rect order you can then click the “Route” tool icon which groups the paths and their order into a new route object. You can have mul­ti­ple routes and again you can then select the routes in the order you wish each route oper­a­tion to take place on the machine. With one or more routes select­ed you can then click the G‑Code tool icon and save the G‑code ready to be run on the machine.

If you are inter­est­ed in watch­ing a basic walk through of the work­flow of the Foam­Cut work­bench there are a cou­ple of videos online, one from the work­bench author and one from myself.

There’s also an excel­lent forum thread with lots of dis­cus­sion as well as lots of usage tips and tricks here.