Setting Up An SMT Line With The LumenPnP
Everything you need to bring SMT in-house
The LumenPnP can greatly increase iteration speed when bringing a product to market. But what else is needed to set up a line and start building boards in house?
Not much! With only a few pieces of equipment and some table space, you'll have everything you need to bring rapid PCBA iteration to your workplace.
LumenPnP setup at WMT GmbH
LumenPnP Requirements
Space
The LumenPnP strikes the balance between easily fitting in most any environment, but also being large enough to handle the vast majority of jobs. A desk or workbench at least 28 inches (71cm) deep will perfectly support a LumenPnP.
If you're planning on using the back rail of feeders, it can be beneficial to leave access to the back side of the machine for easy loading and mounting; we recommend 10in (25cm) extra clearance on the front and back.
Utilities
The LumenPnP is designed to easily fit in any office or work environment without extra considerations. No high-pressure air or ventilation is necessary.
Our CE Certified 140W power supply can be plugged into any standard 120V or 240V outlet; no high-current or specialty power required.
Computer
While most computers can happily run the control software for the LumenPnP, we highly recommend using a laptop running Ubuntu. It's easy to install, and results in better connectivity and camera performance than MacOS or Windows.
In particular, we recommend using the Lenovo Thinkpad T470 as a control computer. It has excellent internal USB hubs, easily handling the bandwidth of both webcams, and runs Ubuntu very well. You can read more about this in our docs.
Conditions
The LumenPnP is robust to changes in environment. In general, avoid extremely hot conditions (90° F / 32° C), or environments with high particulate (metal grinding, bead blasting, etc). Beyond those, the LumenPnP will work excellently in most any condition.
The vision operations of the LumenPnP can be affected by changing lighting conditions. We recommend keeping the machine in a location with controlled lighting that can be kept consistent during operation.
Minimal Config - One Table
An entire functional SMT production line can fit on a single 6 foot by 2.5 foot (1.8m x 0.75m) table. Although more space can help, this is all that's needed to start assembling boards in-house.
Pictured here is the production line we bring to trade shows, where we actively produce PCBAs during the event and hand out to attendees.
Other Equipment
Feeders
Feeders greatly improve the autonomy of the LumenPnP. In general, you'll need a feeder for each unique part used in your PCBA. Wider tapes and parts that aren't used as frequently can be mounted in a strip feeder as well.
If you're not sure what type and how many feeders you need, we've made a simple configuration tool to help you determine what you need for your job.
Stencil Jig
Applying solder paste consistently and reliably is much easier when using a stencil jig, also sometimes called a "paste printer." These jigs index and align your PCB with a solder paste stencil, so it's easy to apply paste to your boards. We use the ubiquitous "3040" printer, and they work wonderfully.
Many PCB fab houses will also manufacture a solder paste stencil for your design. We recommend getting it electropolished if your vendor provides the option; we've found it greatly improves how well the paste releases from the stencil when lifting.
We recommend getting a 370mm x 470mm stencil, as that's what fits on the 3040 printer the best. Also, be sure to select the "Framework" option when ordering, ensuring your stencil comes in an aluminum frame.
Paste
Far and away, our favorite solder paste is Loctite's GC-10. Literally standing for "Game-Changer", GC-10 is a room-temperature stable paste that lasts long after it's listed expiriation date, plus it is completely lead-free.
We've also found it has exceptional performance, greatly reducing the chances of bridging, and always resulting in a strong, clean electrical and mechanical connection.
If you're based in the US, you can pick it up from Digikey, but there are also sellers that ship to the EU.
Reflow Oven
We've tried a number of different reflow ovens, and our favorite is the Controleo3. It's a pre-built, versatile machine that delivers consistent results in a small package; the perfect compliment to the LumenPnP.
Pre-populated with standard reflow profiles, we believe the Controleo3 is the quickest and easiest way to achieve consistent reflow for the LumenPnP.
Want some examples?
See Customer SetupsBoard Design
It's important to make sure that your PCB has fiducials to allow the LumenPnP to find your PCB in space for accurate population. We recommend using a 1mm diameter fiducial with at least a 2mm diameter soldermask opening. This makes them easier to identify by the machine's integrated cameras.
We recommend adding three fiducials located at the outside edges of your board, ideally as far away from each other as possible. The farther at the edges you place them, the more accurate the fiducial calibration should be.
Putting multiple boards into a panel can help increase efficiency when using a pick and place machine by reducing the number of times you need to run a job.
Although it's possible to do this yourself, it's often easier and cheaper to allow your board shop to do this for you; just specify how many of your boards you want in each panel, ensuring the resulting panel can fit in the LumenPnP's build area.
When assembling double sided boards, be sure to use a higher temperature solder paste for the first side, such as GC-10. After reflow, stencil the second side of the PCB using a lower temperature solder paste, then populate that side. When reflowing for the second time at a lower temperature, the first side will not liquify and the parts will stay soldered on.
It is possible to do this with one type of solder paste, but because this relies on surface tension to retain the parts on the first side, we don't recommend it.
You can read more about our design guidelines here.
Maintenance
Especially if your jobs require frequent nozzle tip swaps, the factory-applied lubricant that's been applied to your nozzle might have worn down.
We recommend reapplying some Super Lube (provided in the machine's tool bag) to the O-rings on the nozzle if you find it takes more force to swap tips than usual.
The smallest nozzle tip on the LumenPnP has an opening that's only 0.45mm in diameter!
In order to ensure proper performance, we recommend clearing the opening of this smallest nozzle (called the N045) using a very thin piece of magnet wire every couple hundred jobs or so. Letting the tip soak in isopropyl alcohol can also help loosen up any dried solderpaste.
"The LumenPnP literally paid for itself and a couple packs of feeders on the first production run when compared to using a domestic CM."
- Matt Campbell, Farix Embedded
Conclusion
It has never been easier to quickly iterate on PCB designs. It's both possible and affordable to run quick-turn batches of PCBAs in-house. With only a few pieces of equipment and some spare table space, you can save weeks of engineering time and thousands in outsourcing costs.
