Liteplacer Build Part 3

Partially built pick & Place machine

The third installment in this series covers the construction of the frame/enclosure and the wiring of the machine.  Check out part 1 and part 2 of the build if you haven’t already.

Frame Rendering

I decided to build a dedicated frame & enclosure for my Liteplacer rather than mount the machine to a table like it was designed.  Since the plan is to add feeders and other features over time as needs evolve, the added cost of 80/20 extrusion seems justified.  I had previously designed the frame in Solidworks and the extrusions were ordered cut to length.  All that was left to do was drill a few holes, tap some of the ends and assemble.


Hole drilling with Bridgeport mill
Drilling Holes

Speaking of tapping… why is it that you never seem to break a tap when you have a spare?  But always seem to when you don’t.  Murphy’s law of course came into play… and I ended up donating my only 5mm tap to the scrap bin.

Liteplacer Enclosure Frame With Controls
Assembled Frame With Controls Mounted

Putting this all together necessitated the manufacture of several parts.  A total of 12 custom brackets were manually machined on the ole Bridgeport.  Mounts for the footpads, monitor, PC, and the brackets to mount the Liteplacer into the enclosure were created.  There is something uniquely satisfying about using machinery to build more machines, but all the handle turning really had me wishing for a CNC… more on that in a future post.

The Liteplacer mounts into the frame with a machined bracket at each corner.  I also made up a center bearing support out of some 0.125″ aluminum.  This supports the Y axis shaft center bearing from the frame, and allows removal of the Liteplacer’s rear crossbar.

Cables connected to control enclosure
CNC Control connections

With the machine mounted, it was time to wire it up.  Continuous flex rated cable was used for all the moving runs of wire.  I found some Trex-Onics 18AWG / 6 conductor shielded cable on ebay that was reasonably priced.  The axis motors and limit switches were all wired in using this shielded cable.  The cables were terminated at the control end using Amphenol C 091 A Series connectors to mate up to the control box.

Relocation bracket for Y axis cable guide
Cable guide bracket

The Y axis cable carrier ran a little long for my enclosure and was going to hit the front cover when the Y axis came all the way forward.  I cut a piece of 0.125″ aluminum and formed up a relocation bracket to move the mounting point rearward which afforded me plenty of room.

While the 80/20 extrusion is really nice for it’s adaptability, it doesn’t make for a particularly rigid frame without cross bracing it.  You’ll notice in the picture and rendering at the top of this post that I’ve added some aluminum panels to the bottom, rear and sides of the machine.  In addition to better enclosing the machine, these serve as structural elements, effectively cross bracing the machine in all three directions.  The polycarbonate covers on the upper portion of the machine will also add a bit of rigidity, albeit to a lesser extent than the aluminum panels.

The plates are 0.125″ 5052 aluminum, and the pan that sits just under the open bed area is 0.080″.  These parts were laser cut at a local shop that also did the forming of the “bed pan”.  The polycarbonate covers are 3/16″ thick, and used up an entire 4′ X 8′ sheet.  I laid these out in Solidworks and pestered my buddy Jon until he cut them on his router table.

Most of the polycarbonate covers won’t be installed until the rest of the details are sorted out and the machine is up and running.  I’ve got at least one or two more posts worth of details to cover before the machine is finished.  I still need to build and mount the vacuum reservoir.  I also need to build circuit board and parts holders.  Then it will be time to load software and start placing components.  Thanks for reading and keep an eye out for updates.

Liteplacer Build – Part 2

For part two I’m going to cover the building/assembly and wiring of my custom control electronics enclosure for the Liteplacer.  Part one of this series can be found here, and covers the mechanical assembly of the Liteplacer kit.

I designed this enclosure in Solidworks after some careful measuring of all the goodies that go inside.  With .dxf files in hand, I paid a visit to my buddy Jon and his big router table.  The large vented backplate was cut from 0.125″ aluminum, the end panels and cover were cut from 0.060″.  The engraving of the end panels was done on the router table using a diamond point tool.  The width of the control box matches the small HP computer that will mount vertically just below.

Next order of business was to fire up my little press brake and put the appropriate bends in these freshly cut parts.

I’m pretty happy with how all the pieces ended up fitting together.  I could have made the enclosure just a tad longer though, since it got a little tight inside by the time everything was mounted & wired.

The power supply I used is a 10A/24VDC Delta unit, which happens to be a bit overkill but it’s what I had to work with.  Also, since I’m going to be running a larger 12VDC powered vacuum pump rather than the one that comes with the kit, I mounted a small 12VDC power supply inside.

The vacuum configuration I’m going to run will include a reservoir and an adjustable vacuum switch to power the pump only when needed.  This necessitated a couple changes to the way the vacuum pump FET was wired up.  I ended up using some IRF3708’s for the pump and solenoid valve instead of the STD30NF06L FET’s that were included with the Liteplacer kit.  I put together a perf board to hold these goodies, and mounted it to a couple of the available threaded holes in the big power supply.  The 1N4007 freewheeling diode in the diagram above will be mounted at the vacuum pump motor rather than the perf board for the sake of simplicity.

Connections to the stepper motors, limit switches, solenoid valve, vacuum pump, vacuum switch, and LED ring lights are brought out the rear panel via Amphenol C 091 A Series connectors in 3, 4, and 6 pin varieties.

The USB connector on the Tiny-G board lines up nicely with the provided opening.  One cable gland secures the incoming power cord, and the other is for the IEC pigtail that brings AC power back out to the PC.  The one thing I neglected to consider when designing the enclosure was a place to provide power for the monitor.  I fixed this by manually cutting a square hole in the 0.125″ backplate to accommodate a single AC outlet.  This works but it did make the area behind the front panel more cramped than I had planned.

The front panel houses a pair of lighted rocker switches.  One provides power to the machine via the main power supply, and the other controls power to the vacuum pump.  Three push to reset circuit breakers reside along the bottom.  These provide independent protection for the machine power, the vacuum pump, and the PC/Monitor.  While certainly more than required protection wise, it is nice to have things broken out like this when it comes time to troubleshoot a problem.

The emergency stop I used is a GCX1131 from Automation Direct.  I currently have it wired up to the reset input on the Tiny-G motion control board like is shown in the Liteplacer instructions.  However I’ll probably be changing this to interrupt power to the 24VDC supply instead.  If you look closely you’ll notice that I have a green contact block (normally open) on the e-stop.  This works for resetting the board, but it’s a no no in the industrial control world because the machine won’t stop if a wire in the safety circuit comes loose.  The Liteplacer instructions do however make a point to mention this issue.

With the enclosure all buttoned up, the next step of the project will be to assemble all of my nice new 80/20 extrusion to create the frame that will house everything.  I’ll also need to make up some brackets to mount the PC.  That’s all for today, thanks for reading!

Liteplacer Build – Part 1

I have to admit that placing surface mount components by hand was never my favorite thing.  It’s an activity that’s tolerable if a person only needs a couple of small boards here and there.  However it is quickly becoming a dreaded activity as I have found myself faced with more frequent production runs of 20 or 30 boards, and larger component counts.  For example, I have a control board design that will be ready to prototype in a few weeks that has a component count somewhere in the 300+ neighborhood.  The thought of assembling one of these by hand was enough to get me seriously looking at pick and place machines.

I spent a fair bit of time evaluating the options on the budget end of the spectrum and decided to order up a Liteplacer kit.  I considered everything from designing and building my own machine, to buying a ready to run commercial machine.  The design it myself route was going to take more time than I can afford to devote to such a project right now.  The commercial machines are faster and have more features but came along with a higher cost and a larger footprint.  What attracted me to the Liteplacer is that it’s just enough machine for what I need right now, plus it’s open source & DIY friendly so I can add some of the more advanced features myself as time goes on and needs change.

This first installment is going to be a pretty basic overview of the Liteplacer.  Subsequent articles will cover wiring the machine, and some of the custom touches I’ll be adding during the build.

So… what do you get when you order one of these?

Two boxes full of neatly bagged labeled parts, plus all the makerslides & extrusions to build the machine to the point of being able to attach it to your work surface.  Also included are the cameras for the machine vision functionality, and the Tiny-G motion control board.  It is up to the end user to independently source things like cabling, power supply, monitor, PC, enclosures, and work surface/supporting structure.

There’s not much to say about the mechanical assembly process really.  It was all pretty easy, and well laid out in the instructions.  The detailed labeling was a real help throughout the assembly process too.  The process actually reminded me a bit of assembling a new set of Legos, or Erector sets as a child.

Here’s a closer look at the Y axis drive.  Note: I have not added the belting yet.

Here’s a peek at the gantry.

I added the optional cable carriers when I ordered the kit.  The carriers come a little bit longer than necessary and will hang out in the Y direction.  This isn’t a problem if you are mounting the machine “open air” style like most people do.  However I’m planning to have this machine enclosed, so I shortened up the Y axis cable carrier a bit to reduce the footprint.

The nozzle holder is laser cut from stainless steel and overall, pretty nice.  The included magnets do a good job of retaining the nozzles.  It’s simple yet elegant.


The next step is to build the enclosure for the control electronics and the frame/enclosure for the entire machine.  I drew both of these up in Solidworks.  I’ll be mounting a 21.5″ ASUS monitor on the top horizontal member of the frame.  The PC is a used small form factor HP that will mount vertically just under the control electronics enclosure on the inside left of the machine.

I was originally planning to do a welded steel frame to support the machine, but opted instead for 80/20 extrusion for the added flexibility as I add features over time.

This is the enclosure seen at the left of the frame assembly above.

That’s all for today.  I’ll be posting additional articles as progress moves forward.