Ask the Experts
March 15, 2019
Manual or Automated Assembly?
We are a new start-up assembling wireless sensors. All assembly is now manual, we have no automation. We are at a point where we are experiencing large reject rates due to hand soldering of components. The PCB is a 2 layer board and we are not using anything smaller than a 0805 package.
We were looking at whether we should get better soldering tools or upgrade to small prototype bench-top stencil printing, placement and reflow. We now assemble 10-15 boards per day.
Should we upgrade our soldering equipment, or go for automation?
Expert Panel Responses
We have numerous experiences with customers who are raising up from a startup situation to production - who have successfully implemented bench top manual and semi-automatic equipment.
The choice to go either manual/semi-auto or straight to fully automatic equipment can be based on your resources primarily - and how much of the process you wish to learn and control. If you chose bench top simpler equipment - you will be close to the process and can keep good control over the process - make instruction sheets, and your operators will also learn the process hands-on.
If you chose a more automated line, you will be dedicating more time to equipment training and evaluation - and software, hookups, facilities layout etc.
I would estimate you need a team about double-size to go automated - since one team needs to be doing process development/setup and the other team needs to spec out all the machines and place the orders and see them through installation.
We like the idea - walk before you run, simple as it is, it really fits with electronics production - and you can make many hundreds of boards per day with a simple line - and the setup and clean up are very simple. Enjoy the process it is quite a feat of technology once you have it running!
Mark J. Curtin
Transition Automation, Inc.
Mr. Curtin is the founder and president of Transition Automation, Inc. Their main product is Permalex Edge Metal Squeegees. They also sell the PrinTEK Ultra-Fine Pitch stencil printers. His background includes 25 years of designing squeegees and SMT printers. He is closely familiar with the SMT printing process, squeegee design, and all aspects of in-line printing machines, double-sided tooling, stencils and solder paste performance.
Here's a different idea:Buy your PCBs pre-pasted. Pre-pasted PCBs come with assembly-thickness solderready-to-go right out of the box. No stencil to buy, no paste to print. There'seven a tacky flux coating to hold everything in place. I probably shouldn'tname service suppliers so just web search "solid solder deposit" thencheckout the hits.
Robert "Bob" Lazzara
Circuit Connect, Inc.
Bob has been in PCB design and fabrication since 1976. He has held elected positions with the SMTA, is a member of the MSD Council, has served as a committee member for various IPC standards and is a Certified IPC Trainer.
Iwould recommend a small prototype line.
Steven Pollock has worked in the industry for OEMs, and large CMs before moving to application Sales. Pollock has been working in SMT industry for nearly 20 years.
Tough question without knowing what soldering equipment, supplies, or the state of your components/PCB's you are using, as well as what the defects you are seeing are.
First and foremost, you need to truly understand the root cause of your defects. Solder and Inspection training will probably do a ton for improving your quality, provided you feedback what you find to your assemblers. If you have very "cheap" equipment or are lacking good quality materials such as flux, solder, components or PCB's, you are at an extreme disadvantage out of the gate. No amount of training can completely overcome that.
Knowing how to properly use and maintain the soldering iron tips is critical as well. If you don't feedback the defects as well as understanding the root cause of the defects, they will continue to occur. Usually it breaks down to one or more of these items: Bad material, bad training, bad workmanship, or bad process.
If you automate your process, you will have very controllable and repeatable results if you set your process up correctly and monitor it on a consistent basis. Don't go into it without doing proper research or without getting some consulting on not only what type of equipment to get, but how to set up, maintain and consistently improve the process.
Automating your process will speed things up, you will likely go to more than 10-15 PCB's a day, but possibly at a significant investment. Remember though, if your process isn't good, you could be turning out more defects than you are now, and at a much, much faster rate.
Esterline Interface Technologies
Mr. Hughes has been in the electronics manufacturing field for 20 years. Operating the processes and as a manufacturing engineer for the last 14 years. He is also a CIT as well as an SMTA Certified Process Engineer.
Weoffer a desktop printing stencil kit to lessen the amount of time spent anddefects associated with hand soldering. The cost of the stencil kit isminimal, and would be a great solution until the ROI on more automatedsolutions make more financial sense.
Integrated Ideas & Technologies, Inc.
Stephanie Nash is the Director of Technical Services & Marketing for Integrated Ideas & Technologies, Inc., a premier manufacturer of SMT stencils. She has been instrumental in the stencil design and technical support.
Thereare three options in this case:
- Small bench-top stencil-reflow system is one option.
- Outsource PCB assembly to regular contract manufacturer for assembly of boards on a SMT line.
- If the volumes are not that large, get your operators trained to IPC-A-610E and develop a Hi-Rel Assembly facility where most of the soldering and inspection is done under magnification.
Astra Microwave Products, Hyderabad, AP India
Holds Degree in Engineering, started off as Scientist/Engineer in ISRO (Indian Space Research Organization) in Quality Assurance of Space hardware Electronics Production. Worked in the area of Parts, Material and Process; DPA, FA and Process Qualification for space and ground hardware. Later moved into Private sector and worked in the area of Quality Management Systems & ISO 9001 certification. Currently hold a position as Head-Quality in RF/Microwave Product manufacturing for Defense and Aerospace segment.
Even moderate levels of automation can have huge benefits. I would definitely recommend starting to move down the path to automation. A hand-printing set-up is very workable for all but the finest pitches. For 0805 and larger, you can hand-print very easily.
Component placement will definitely be the most problematic operation to automate, and for the time being you could certainly keep this a manual process and introduce automation at a later date.
Reflow can be done relatively economically and repeatably in benchtop reflow systems. You don't need a long machine with a lot of heat zones, especially since your parts will have relatively low mass.
In addition to the benefits of more repeatable solder volumes and wetting, there is another benefit to automated soldering; you will no longer have to be hand-soldering multi-layer chip capacitors. Doing so does create a reliability risk, more for some parts than others.
Fritz's career in electronics manufacturing has included diverse engineering roles including PWB fabrication, thick film print & fire, SMT and wave/selective solder process engineering, and electronics materials development and marketing. Fritz's educational background is in mechanical engineering with an emphasis on materials science. Design of Experiments (DoE) techniques have been an area of independent study. Fritz has published over a dozen papers at various industry conferences.
A simple alternative process might be SIPAD where you send circuit boards out to have the SMT pads coated with solder, then a tacking flux is added. For assembly, remove the film covering the tacky flux, place the components, then reflow using any means of heat i.e. hot air or small bench top oven. I believe Amitron is now offering this service, contact is Matt Kehoe
Mike Burgess, ASM Assembly Systems, LLC