FreeCAD News

It’s an amaz­ing age for mak­ing things, and an even greater age for mak­ing things using open source solu­tions. At our recent FOSDEM stand we shared the booth with KiCad, the open source elec­tron­ics envi­ron­ment. It was fab­u­lous at the event to see items and machines made using KiCad and FreeCAD in com­bi­na­tion. It’s also quite amaz­ing to con­sid­er the com­plex print­ed cir­cuit boards (PCB’s) KiCad can cre­ate with the tiny com­po­nent pack­ages placed and sol­dered into high­ly accu­rate positions.

Beyond the mere won­der of it all, it’s inter­est­ing to delve into how these com­po­nents might be placed on a PCB. For small, sin­gle unit, home hack­ing, adding sol­der paste and plac­ing each com­po­nent with a pair of tweez­ers before heat­ing the entire PCB is not uncom­mon. Step­ping up in com­plex­i­ty you may man­u­fac­ture a sten­cil to add the sol­der paste quick­ly and accu­rate­ly. How­ev­er, when it comes to mak­ing lots of devices with lots of com­po­nents then the best solu­tion is “Pick and Place”.

Pick and place uses a robot­ic sys­tem to load the com­po­nents from reels with some kind of actu­a­tor pick­ing up the com­po­nent and accu­rate­ly plac­ing it onto the PCB. It’s exact­ly the tech­nol­o­gy that large PCB assem­bly hous­es use to cre­ate all man­ner of devices. 

LumenPnP is an open source pick and place machine and bril­liant­ly all the CAD parts have been designed in FreeCAD. From a dis­tance LumenPnP might look like a CNC router as it has X, Y and Z axis cre­at­ed with pre­ci­sion lin­ear rails. The tool head how­ev­er fea­tures two noz­zles each of which pro­vides suc­tion to car­ry elec­tron­ic com­po­nents. The machine clev­er­ly has two camera’s which enable it to detect fidu­cial mark­ers to accu­rate­ly align to PCB jobs.

LumenPnP uses a very slight­ly tweaked ver­sion of the open source Mar­lin Firmware, more com­mon­ly found in 3D print­ers. For soft­ware the sys­tem relies on openpnp — a great choice with baked in sup­port for KiCad. This makes it triv­ial to set up posi­tion­al files for the com­po­nents on project PCB’s.

The machine is avail­able to pur­chase from Opu­lo, but every­thing is open source and you could build your own. It’s a great sys­tem that could save you time and mon­ey depend­ing on what vol­ume of PCB’s you are plan­ning to populate. 

Look­ing through the repos­i­to­ry you can find that all the CAD work for mechan­i­cal com­po­nents is com­plet­ed in FreeCAD, with KiCad being used for all the PCB’s. So if you own a LumenPnP you can eas­i­ly cre­ate replace­ment parts, or indeed you might think of a way to make a mod­i­fi­ca­tion to the design to suit your par­tic­u­lar needs. It also means that it’s open to com­mu­ni­ty con­trib­u­tors with­out tying them into pro­pri­etary tool chains.

Look­ing around the Opu­lo site we can also see that there are prob­a­bly more over­laps and uses for FreeCAD. In one video, a bril­liant PCB, shaped like the OSHW logo, is being pop­u­lat­ed with LED’s. It’s mount­ed onto the machine in what appears to be a 3D print­ed con­for­mal jig. This work hold­ing approach means that it’s fast to swap in unpop­u­lat­ed PCB’s accu­rate­ly keep­ing the process run­ning with min­i­mal reset­ting. We’d haz­ard a guess that this mod­el was made in FreeCAD, with step out­put export in KiCad, it’s pret­ty easy to make a jig like this. There’s even more crossover between FreeCAD and KiCad with the excel­lent KiCad step up work­bench that makes it pret­ty triv­ial to make cus­tom com­po­nent mod­els that inte­grate into the KiCad foot­print sys­tem per­fect­ly as well as mechan­i­cal­ly mod­el­ling to your PCB design.

All in all it’s excel­lent to see all these open source projects and com­mu­ni­ties over­lap­ping cre­at­ing new and inter­est­ing tools and approaches.