Potential Processes for Automation

Step 2: Identify Potential Processes for Automation

At this point, we need to discuss the strengths and limitations of process automation with collaborative robots. In fact, you probably already have a bunch of ideas as to what processes you would like to have automated I am afraid to say that most of the tasks you thought were good candidates for automation are probably not the best choices to begin with. We need to be realistic about what the technology can do today. Some applications are easier to automate than others and as a first integration you should start small and simple. Ideal tasks for a first collaborative robot are tasks that are highly predictable and repeatable. These are easiest to automate with a collaborative robot.   Easy to automate Harder to automate Repetitive tasks in which the robot does not apply force Pick and place Dispensing Complex logic or decision making tasks Projects that require sensors Vision Force-torque sensor Parts Little part differentiation or changeovers between similar parts Part presentation: Ordered part, structured on a table, matrix or tray Parts High changeover rates for parts with divergent properties (size, shape) Deformable parts Part presentation: Moving conveyors Unstructured presentation (bins) Interacting with fixed objects, such as boxes. Integrating communications with other machines Location controlled processes: Always pick in the same place Always place in the same place Force controlled processes: Grinding, polishing, drilling, Precision assembly Processes requiring specialized or human know-how Welding Painting   Tip: To create a quick simulation, perform the task and think about whether you could do the same task without seeing or feeling the part, its weight or the force applied by the part. In other words, could you do it blind? This will give you an indication of what kind of sensors you will need.   What’s easy to automate ? For a first automation project, the options below are recommended to enure an early success. Repetitive tasks: Robots are good at repetitive tasks and endurance applications. If you have an application that repeats the same motion all day, it is a good candidate for automation by robots. One place to look for these types of applications are places where you have repetitive stress injuries in your workers, or places that have been identified as high risk for these kinds of injuries. Part presentation in pick and place: Ordered parts: A part or a series of parts that are always in the very same position during the whole process are easy to automate. The robot will basically repeat again and again the same motion without asking any questions - or getting injured. Similar parts: Parts with similar properties: dimension, weight range or physical appearance allow for easier transitions between production changeovers and will ensure that the robot can handle these parts without tool changes. Dispensing: The part is going to be placed somewhere that requires precision, so that the part will drop in the same spot each and every time. This is an easy dispensing process. Requiring more precision is tougher, but not impossible. Matrices and trays: If you have a matrix of parts (i.e. 10 x 10 parts), or if they come in trays (for example, if you’re handling small parts), you can teach the robot how to pick each part in the matrix or tray by simply programming the initial position, ending position and the number of parts in each row and column. Fixed matrices or trays are the easiest processes to automate, but in the case of a tray, you can also program the robot to remove and bring a new tray to the spot where it will pick the parts from the tray. Keep in mind that Universal Robots offers wizards (an on-screen dialog) to automate these types of picking applications. Their wizard is embedded in the robot controller logic and can be engaged very quickly.   What’s complex to automate ? For a first automation project, we don’t recommend choosing the applications below. While they can be automated, the more complex your robotic cell, the more time, energy and money you will spend on it. It’s better to start small and increase the level of automation difficulty at the same time as you increase your automation experience. Part presentation: Unstructured part presentation: If it’s hard to find a part with your hands, it will also surely be difficult for the robot. In fact, if the parts are presented in different positions and orientations each and every time, you will need a little bit more intelligence than just a robot arm. This means more programming, and possibly sensors. Widely divergent parts: Parts that are unalike in dimension, weight range, physical geometry or that are deformable often require tool changes as well between production changeovers. While this certainly can be done, it will add a greater level of complexity to your automation project and is probably not a good place to start for a first robot integration project. Conveyors: With a little more complexity, it is possible to automate conveyors too. However, you will need to figure out details such as: speed, relative position and other specifications related to time / movement / displacement. This is another case where you will need programming to make it work Sensors: If you need to integrate any type of sensor, such as vision or force torque, the level of complexity rises. You will need to plan for more integration time and a higher cost to automate the cell overall. Integration with machines: You might need the robot to interact with a machine so they can communicate with each other. This is a relatively simple process, but can be difficult if you have never worked with automation. If you can skip this step, you are one step closer to simplicity. One trick is to have the robot use the machine interface that was built for humans, such as a manual door and a start button for example. Alternatively, a simple digital I/O wired between the machine and the robot can be used. Logic: If the process is complicated in terms of logic or if it involves decision making, this will add complexity to the robot program. If you are new to robotics, try building your programming skills with simpler tasks before attacking these types of problems. Force control related tasks: If you want the robot to grind, polish, drill, weld or paint; these processes can certainly be done by robots. But processes that require a specialized or human touch are much more complex. For the robot to go from A to B is easy. Having a robot follow a trajectory while applying a specific amount of force in a specific process is more difficult, both in terms of sensor integration and programming.   In conclusion, collaborative robots are really good at pick-and-place, material handling, and material dispensing; but applications that require applying force and momentum are going to be more complex. Again starting simple and building up expertise is the approach we find has worked best. If you’d like to explore more on applications for collaborative robots, here are a series of videos that might prove useful: Collaborative Robots Case Studies   Get the PDF version for this step here.   What's next?  Here are the upcoming chapters in our 5-step practical guide: Week 3: Get the team on board with robots. Week 4: Assess your potential applications. Week 5: Get management on board with robots.  We hope you find this series useful in getting your first robotics cell in your factory. Want to discuss your challenge? Request a consultation with our robotics applications experts.

IPC - Product Compliance Requires Supply Chain Transparency

Feed: IPC Blog
Posted on: quarta-feira, 9 de março de 2016 11:29
Author: IPC
Subject: Product Compliance Requires Supply Chain Transparency

By Tord Dennis, WSP USA Changes to the RoHS, REACH, and conflict minerals regulations make the need for supply chain transparency more crucial than ever. The European Court of Justice (ECJ) ruled in 2015 that the 0.1% threshold for notifying SVHCs ( Substances of Very High Concern) in articles applies to “each of the articles incorporated as a component of a complex product” and not to the entire article. Companies that file with the SEC must annually determine and report the sources of tin, tungsten, tantalum, and gold (3TG) in their products under section 1502 of the U.S. Dodd-Frank Wall Street Reform and Consumer Protection Act. Suppliers cannot afford to claim “confidentiality” or ignorance to the material and substance make-up of the products they sell that become part of another company’s product. Leary of public backlash and/or legal action, some OEMs are taking drastic measures such as discontinuing business with suppliers who do not give them the information they need in a timely manner. Full material declaration (FMD) is quickly becoming the “gold standard” data requirement for an OEM to accurately assess the risk of restricted materials in a product. This means that suppliers must deliver the complete material and substance breakdown of their component/product in a manner that puts the least amount of impact on their core business activities and enables the OEM to collect and aggregate similar information from other suppliers. IPC has developed a family of standards dedicated to this task. The IPC-175x family of standards (e.g., IPC-1752A for material and substance declaration and IPC-1755 for conflict minerals) establishes a standard reporting format for data exchange between supply chain participants. It defines the information that most companies need to collect in order to prove compliance. It also specifies an XML-schema which enables more efficient and effective exchange of data by enterprise data systems. Automating the exchange of FMD data is made simpler with the adoption of the IPC-175x family of standards but other critical elements must be in place to achieve success. The OEM needs to build a product stewardship process that enables them to efficiently collect and analyze the FMD data from their supply chain. This means they must have executive level support and a well thought out implementation plan for enterprise software to manage this data. The OEM and the supplier must commit to being partners in this venture; “no data means no business” for all parties involved. A statement must be included in supplier contracts that require documentation pursuant to any government’s legal requirements regarding restricted materials and substances. To learn more, attend technical conference session, S03 at IPC APEX EXPO. I will present a paper titled, “Best Practices for Product Environmental Data Collection,” on Tuesday, March 15, 2016 at 2:00 pm. To learn more or register for IPC APEX EXPO, visit www.ipcapexexpo.org. Filed under: Conflict Minerals, Environment, Health and Safety, Government Relations, IPC, Legislation, Regulations, Standards Tagged: conflict minerals, European Court of Justice, full material declaration, IPC APEX EXPO, IPC-1752A, IPC-1755, IPC-175X family of standards, REACH, ROHS, SVHC

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WHAT ABOUT FINISHING WITH A COLLABORATIVE ROBOT?

Finishing applications

With manufacturing processes becoming more and more automated, operations such as finishing are among those that are considered dangerous for human workers. With the introduction of robots that can work close to people without exposing them to hazards, it is now less risky and a lot faster to use a robot for your finishing application.  WHAT IS FINISHING? Depending on your manufacturing process, finishing can use different methods. Some of the most popular applications are sanding, deburring and polishing. As your job is basically to finish a part, you probably have already mastered this method. But you still need to figure out how to do it with a robot! Here's where we can help.  WHAT ABOUT FINISHING WITH A COLLABORATIVE ROBOT? A collaborative robot or cobot for short is a general term used to describe power and force limited robots, robots that can be used without safety guarding or that have incorporated other safety features. This means the cobot can be put beside a machine or a person and set to perform a certain task without needing to be fenced off from its surrounding environment. That being said, to introduce a cobot in a finishing application and program it to deburr or sand parts is not as simple as it sounds. You will need to choose a robot and tools that can accomplish the job and that can reach a level of performance comparable to a human worker. Here are some key factors to consider if you are looking at a finishing operation using a collaborative robot.  Robot Specs Payload : The payload is the total weight the robot can carry. You need to weigh your end effector, the heaviest raw part or tool you want to carry, plus you need to account for any force that is needed in the finishing operation. This will determine your robot payload Tip 1: Remember with power tools or other kinds of tools, you must consider their relatively high mass. The robot needs to include this in its payload. Tip 2: If you are applying force on a part, you need include this in the maximum rated payload as well.    Ease of programming: Finishing usually requires irregular paths that imply curves, acceleration, speed control and other complex programming methods. You may want to start with a simple application and build your experience on this one before going into a process that requires precision force and/or precision paths. Gripper Specs Force Feedback: Finishing requires force feedback. Using a force torque sensor will allow you to have consistent force and pressure applied on the product along a given path. This means you can limit the force at a given point and/or set a force threshold that should not be breached on a given cartesian path.. Tip 1: Make sure the force torque sensor is not interfered with by external signal noise. Tip 2: There are 2 ways to have force feedback: by placing the part on a fix force torque sensor or by monitoring the force applied by the robot directly at the robot wrist. Required Workspace Safety: The robot will work alongside humans. Some people will be aware of the danger this presents, others won't. Make sure to perform a risk assessment before building your automation project. Once you're ready to go live, make sure everyone is trained on safety rules around the robot and the risks involved with using a robot. Collaborative robots can increase the safety of your applications, but there may still be risks for your workers. Tip 1: Use ISO the standard to guide your risk assessment and don't forget to consult local regulations on this subject. To learn more, download this eBook on risk assessments for collaborative robots. Tip 2: Remember, even if the robot itself is safe, if the tool or the part it carries is dangerous, then the robot cell itself may have risks for your workers. Machine Interface: Make sure to interface your robot with the machine you will be using: Conveyor belt, power tool, etc. Tip 1: This seems simple, but this is probably the most underappreciated part of the process. Make sure to reserve time and budget for this one.  There you have it, the basics of robot, gripper and workplace specifications for using a cobot in a finishing application. If you need more information on how to shop for a collaborative robot or what their key features might be, we have put together a complete eBook on this subject.   We have created a robot cheat sheet to help you choose which specifications you need to look at depending of your application. Also we have created a work sheet, which will help you to actualize your process data, so that you have this information all in one place when you go to talk with your local robot distributor.   Want to discuss your challenge? Request a consultation with our robotics applications experts.

Effects of Ultrasonic Cleaning

April 12, 2016

Effects of Ultrasonic Cleaning

http://www.circuitnet.com/experts/52525.html

Does ultrasonic cleaning have an adverse effect on crystals or other components on a PCBA?
If there is a negative affect are there any ultrasonic cleaning methodologies that would prevent problems?

K.U.

Experts Comments

The answer is no. The answer is yes. Take your pick. There are two schools on this subject. Smart, intelligent, and experienced engineers will tell you that there is significant risk of component damage when exposed to ultrasonic energy. From damaged crystals to wire bond fractures, that fact is that there is the possibility of damage. In fact, several years ago, a major assembler of electronic assemblies published data linking component damage to ultrasonic energy. In reality, while the above statements are true, the chance of component damage on modern ultrasonic cleaning equipment is rare. Modern ultrasonic cleaning equipment utilizes frequencies of 40 kHz. The frequency is "swept" up and down to reduce potential component damage. Also, if the watts to fluid volume is low enough, damage will be further reduced. Here's the real issue. It doesn't really which school of thought you subscribe to. What matters is what your customer, QC manager, reliability engineer, and others think. The fact that there is legitimate belief that ultrasonic energy has the potential to cause component damage normally precludes it from being used to preform a defluxing process. The fact that you are asking this question, illustrates my point that ultrasonic energy is not openly accepted in the defluxing world, despite compelling arguments to the contrary. I would strongly recommend spray-in-air technology for your cleaning / defluxing requirements. It is universally accepted as the conventional wisdom for defluxing applications and is never suspected of contributing to component damage.

Mike Konrad President Aqueous Technologies Mr. Konrad has been in the electronic assembly equipment industry since 1985. He is founder and CEO of Aqueous Technologies Corporation, a manufacturer of automatic de-fluxing equipment, chemicals, and cleanliness testing systems.

We have several published articles available for download on our web site, click on the "Recommended Reading" button. The article by B.P. Richards et al. "Does Ultrasonic Cleaning of PCBs Cause Component Problems: An Appraisal" best addresses your question: "Does Ultrasonic cleaning have an adverse affect on crystals or other components on a PCBA?" My paper, "Reducing the Cost of Misprinted PCBs", addresses the parameters that would help prevent potential problems. I also recommend the IPC-7526, "Stencil and Misprinted Board Cleaning Handbook."

Bill Schreiber President Smart Sonic Corporation Mr. Schreiber developed the original ultrasonic stencil cleaning process in 1989. Obtained the only EPA Verification for specific parameters of Environmental Safety, User Safety and Cleaning Efficiency for a stencil cleaning process.

If the frequency of the crystal matches the frequency of the ultrasound, then there is resonance and the component can fail. Regular cleaners are better than ultrasonic cleaners precisely for this reason.

Karthik Vijay Technical Manager - Europe Indium Corp. Currently with Indium Corporation and responsible for technology programs and technical support for customers in Europe. Over 15 yrs experience in SMT, Power, Thermal & Semiconductor Applications. Masters Degree in Industrial Engg, State University of New York-Binghamton.

In the early days of integrated circuits, say the 1960s and 1970s, ultrasonic cleaning was generally not used for cleaning components. The affect was not on the crystals or components themselves, but on the leads going through the packaging. Repeated, high-powered ultrasonic cleaning simply vibrated the leads too strongly, causing metal fatigue and component failure. This was particularly true for military and aerospace systems, which actually banned ultrasonic cleaning in one of the now-long-forgotten mil specs. Modern ultrasonic cleaners use "sweep" frequency management to avoid this problem. The machines change frequency constantly, so the energy is never on a harmonic frequency of the lead for very long, and never at the same power setting, which has been proven to minimize damage to components. At the same time, I think every expert would urge careful and thorough testing on your boards, your components and your systems before certifying the process to be trouble-free. A better answer might be to look at vapor degreasing. Vapor degreasing is a much gentler form of cleaning that does not need ultrasonics to work well. Check out one source at Micro Care, Why is Cleaning With Vertre Better than Cleaning With Water or Some Other Solvent ? or another option is Does MicroCare Have Any Solvents Suitable for Use in Vapor Degreasers?

Mike Jones Vice President Micro Care Mr. Jones is an electronics cleaning and stencil printing specialist. Averaging over one hundred days a year on the road, Mike visits SMT production sites and circuit board repair facilities in every corner of the globe, helping engineers and technicians work through the complex trade-offs today's demanding electronics require.

Pin-in-Paste Hole Fill

July 7, 2016

Pin-in-Paste Hole Fill

We are about to implement Pin-in-Paste technology.

How can we ensure proper plated hole fill during the screen printing process? Will the process require using a different solder paste than the one we use for pure SMT assemblies?

R. L.

Experts Comments

 

Paste-in-hole processes are somewhat more complex than traditional SMT from a process control standpoint, but with good engineering practices and the properly optimized stencil, it can be a very controllable process for many users. The key is doing some math on the front end and determining how much paste will be needed to fill the space between the barrel of the through-hole and the lead of the component. Since paste is generally about 50-55% metal by volume, you will generally find that you need to overprint the pad area to ultimately deliver enough solder to the solder joint. Various stencil design techniques will work; contact your solder paste and/or stencil supplier for more detailed pointers. As for picking the right paste for paste-in-hole applications, many standard solder pastes may drop into this type of process without any issues. However, there are two additional solder paste performance requirements for paste selection in paste-in-hole versus traditional SMT. These include coalescence behavior and anti-dripping behavior. The coalescence behavior becomes more of an issue than usual due to the likelihood of overprinting onto the solder mask on the top side of the board. The anti-dripping requirements stem from the fact that some pastes can drip off the bottom of the component lead upon heating, resulting in less solder than expected for the solder joint. This can be avoided by selecting a solder paste that was designed not to drip in a paste-in-hole application.

 

Brian Smith General Manager - Electronic Assembly Americas DEK International Mr. Smith has been supporting customers in the electronics assembly industry since 1994. His expertise is focused on solder paste printing and reducing soldering defects. He holds a BS in Chemical Engineering and an MBA in Marketing. He has authored several papers in trade magazines and at industry conferences. He is an SMTA Certified Process Engineer.

To ensure proper plated hole fill during the screen printing process you must have the proper volume of solder paste. Here's an example of the formula you can use: H=Hole diameter D=Lead diameter T=Board thickness L=Width of lead in the X direction (For square lead) W=Width of lead in the Y direction (For square lead) Pi =3.14 Hole Volume (HV)=(3.14)(H/2)(H/2)(T) Lead Volume (LV)=(3.14)(D/2)(D/2)(T) (For round leads) Lead Volume (LV)=(L)(W)(T) (For square or rectangular leads) Annular Ring Area(RA)=(3.14)(L/2)(L/2)-(3.14)(H/2)(H/2) Solder volume (SV)=HV-LV Print Volume (PV)=(2)(SV) (50%) Print Area (PA)=(F)(PV)/stencil thickness F=Inspection Factor .7=no fillet .9=fillet on both sider 0.8=fillet on primary side 1.0=large fillet on both sides

 

Joe Karcewski Product Manager APS-Novastar, LLC Joe Karcewski has been a Process Engineer for 16 years in the industry. He is a certified IPC-A-610 trainer and is presently working at APS-Novastar as a Product Manager for Soldering Systems including Selective Soldering systems.

The best solution for the Pin-in-Paste process is the ProFlowR enclosed head system. The main reason for this is that ProFlow allows independent control of paste pressure and, therefore, the ability to control the amount of paste fill for the through-hole apertures. If you are unable to use ProFlow, then a 45 degree squeegee can increase the paste pressure. But, if the board is thicker than 1mm, several print stokes will be required, which could degrade the SMT deposits. Standard solder paste should be used for this application.

 

Clive Ashmore Global Process Manager Dek Printing Machine Mr. Ashmore is responsible for the Global Applied Process Engineering group for DEK. Clive specializes in all aspects of manufacturing engineering, with special emphasis on mass imaging technologies.

Same paste should work. You can calculate amount of paste required knowing 4 items: pin dimension, board thickness, hole size, and annular ring size. Paste to solder shrinkage is usually about 50%. Paste volume can be achieved in 3 ways: Overprint, Step-up Stencil, through-hole paste fill. Good reference paper is in SMT Magazine Nov and Dec 2006 "Intrusive Reflow for Lead Free paste."

 

Bill Coleman Vice President Technology Photo Stencil For over 18 years, Dr. Coleman has been the vice president of technology for Photo Stencil, working closely with customers to understand their printing requirements. His efforts have resulted in several new stencil products.

The use of an off-line x-ray inspection system post paste that offers oblique angle views without tilting of the actual board to inspect a representative sample of boards will allow you to see the amount of paste that is located down the holes prior to reflow, non-destructively. The same test can also be used post reflow to quickly confirm that the resultant pin-in-paste hole fill meets the IPC 610D recommendations of a minimum of 75% fill.

 

Dr. David Bernard Product Manager Dage Precision Industries Mr. Bernard has been the X-ray Systems Product Manager at Dage for over 5 years and have been involved in all aspects of x-ray inspection and test for printed circuit board assembly applications. Prior to this, Dr. Bernard was working with radiation measurement instrumentation.

There are numerous tradeoffs to consider when pin in paste hole fill is the goal. First, overprinting can be problematic due to the possibility of mid chip solder balls. Step stencils are more expensive than standard stencils, and will likely result in reduced throughput and material expense due to the need to increase underwipe frequency. One technology which is becoming very popular is the use of solder preforms in tape and reel packaging. The preforms come in standard sizes, such as 0402, 0603 and 0805 to name a few. They are packaged exactly like chip capacitors and resistors. Placement is done after paste printing. Only 20-25% of the preform needs to contact the solder paste. Since the preform is solid metal, a preform as large as four times the volume of the paste volume can be added and still achieve perfect reflow results.

 

Paul J. Koep Global Product Manager Alpha Mr. Koep is responsible for product planning and technical marketing for the Preform Products at Alpha. He is the co-author of several patents in the areas of soldering applications focusing on reflow and alternative methods.

Reader Comment Readers may be interested in the free ebook on "Pin In Hole Intrusive Reflow Design and Assembly" at http://www.pihrtechnology.com The most common problem with the process is the hole to lead ratio, at the design stage its easy to change and it gives design engineers more tracking space. Changing the hole to lead ratio on existing design is easy too as its not going to impact reliability either. Bob Willis, Bobwillisonline.com, UK

Reader Comment Going into the reality of pin-in paste requires a little more than applying paste into the hole. There are usually unforeseen issues which occur after the pin in paste operation. The stencil can be designed to prevent inadequate hole fill by forming a cross pattern with the paste around the top side of the hole. The flux will stay mostly on the top of the pcb under the part instead of flushing out to the bottom pad. The flowed solder will only take what is required to do the job. Making the use of expensive preforms is not necessary. People are asking for advice or suggestions as to which way to perform their particular task at hand. They may not be aware of the pitfalls of following this advice. I know I would prefer to also know what I shouldn't do as well as what I should. Mark A. Maheux Sr., Sr. Manufacturing Engineer, Honeywell Life Safety, USA

 

 

http://www.circuitnet.com/experts/58115.html

Packaging - Shock-n-vibration sensitivity assessment

Packaging - Shock-n-vibration sensitivity assessment from Marcelo Chirai