Late last year, a renowned Scandinavian telecoms company took a fresh look at its hand assembly process used when manufacturing its cellular base station products. The company trialled a Sigma workstation, liked it, and so purchased it.
Then the process engineering team decided they really liked it. So they purchased three more. As if to prove that good things come in threes – we now hear that they are to purchase a further three Sigma workstations later this year.
As well as the Sigma workstations, the company has invested in our Workflow software. Workflow lets the team maximise productivity and traceability by collecting and analysing production data from every Sigma station to track throughput against work schedules in real time. It logs critical production data too.
Finally, proof of some really productive work from the Chancellor of the Exchequer, George Osborne MP! But only for 10 minutes – probably not enough time to map out a new funding package for British industry. Or was it…?!
During his visit to Chippenham-based electronic control and lighting specialist DANLERS in July, the Cabinet Minister and Rt. Hon. Member for Tatton took interest in a Mascot workstation and tried his hand at guided PCB hand assembly. DANLERS has three Mascot Pushtrack systems set in a ‘Lean Line’ configuration – amusingly appropriate given the lean economic times we’ve all endured over the past few years.
Reliable reports from the DANLERS’ staff who observed the Chancellor at work are that his hand assembly skill is pretty competent. But then it’s really hard to get things wrong using a Mascot – even a politician can do a good job! Mr Osborne was tutored on the Mascot by DANLERS Production Trainee Mathew Johnstone.
The primary purpose for Mr Osborne’s two-day visit to Wiltshire was to support Michelle Donelan, the prospective MP for the Chippenham Constituency, and to announce multi-million pound Government grants aimed at creating or securing thousands of jobs. DANLERS Limited was selected by the local Conservative office as a fine example of a successful local company that has maintained its status as a UK manufacturer, resisting the trend to manufacture abroad.
An established multidiscipline engineer (also a 3D CAD wizard) with a passion for technical product design…and tennis!
Business Development & Support
An aerospace served engineer, my role is to develop new business and support existing customers on a UK and International level.
A qualified Management Accountant with an organisational job role which involves much more than just crunching the numbers!
Could this be our most intriguing Sigma application? Okay, some of you may ask “What’s Sigma?” as it is perhaps our best-kept secret. Despite our secretiveness, there are quite a few Sigma workstations being pressed into service in the marketplace. This particular application sees the hand assembly system selecting ceramic ball bearings for precision ball races.
The real power behind the clever ball bearing selection process with this Sigma workstation is our new Data I/O card. This accessory permits Sigma to be programmed to offer parts based on live incoming data – in this case a measurement being made of the precision ball race cage. Once this fine-tolerance measurement is passed to Sigma, the workstation presents the assembly operator with the best matched set of ceramic ball bearings from the appropriate tray of a single motorised carousel. It then guides the picking process using a suction cup, allowing the operator to take eight ceramic balls.
These ceramic ball bearings vary minutely in size, due to the natural tolerance of the manufacturing process. However, when each ball is accurately measured, sets of the same size (strictly gauged within very tight tolerance parameters) can be grouped into a carousel tray segment. Sigma knows the exact measurement of each of these ball sets and offers them up according to the incoming measurement via Sigma’s Data I/O card. It’s essentially blue-printing – a procedure used widely in the performance automotive sector, especially for sports car and motorcycle engines. In this way, the assembly operator can only build a ball race to the exact measured quality.
Talking of performance, these premium ball races make their way into turbocharger units, where rotational velocity can exceed 150,000 rpm! At these speeds, any slack or play in the ball race could cause catastrophic vibration. Similarly, while ceramic balls are less prone to thermal expansion, a bearing race that is too tight can seriously degrade rotational performance. That’s why the precision measurement and matching process is so critical. And that’s also why the Sigma workstation with its new Data I/O card is so important.
The turbo units manufactured by this Sigma customer are used in top-brand German performance cars.
One of our high profile customers in the US, a large manufacturing giant, set us a challenge to optimise the handling of its high density PCBs on Mascot workstations. The assemblies are double-sided legacy defence boards, comprising a mix of surface mount and through-hole components. It’s fair to say that they are quite bulky.
During the Mascot guided assembly process, the boards must be flipped over at nearly every single assembly step. Operators need to be able to do this while armed with a soldering iron in one hand. As most operations process engineers will know, this is fraught with problems and presents for too many opportunities for human error.
We came up with a great solution: a gimbal-mounted frame that holds the board by its edge. It features multi-axis movement too, mainly because the customer’s boards are too large to flip over without lifting them away from the table surface – yet another challenge for the poor operators!
Then we extended the functionality even further; As the operators already have their hands full, we automated the vertical axis movement by adding a foot pedal to drive a height-adjustable actuator – it seemed a natural progression! So there are three pedals in the system – one to step on in the Mascot assembly programme, one to raise the board holder and one to lower it. Couldn’t be simpler!
Also, when the operators flip the board over in its gimbal mount to access the other side, the Mascot software automatically switches to display the relevant auto image corresponding side of the PCB while the laser head mirrors its coordinates to highlight the exact spot on either side of the board.
The first gimbal mount system was installed at the customer’s site just a couple of weeks ago by EAP, our US agents. However, this week our intrepid development engineer Martin Laidler, has crossed the pond to the US to visit the facility and optimise the installation. The customer has already ordered three more gimbal mounts based on our initial prototype and have ring-fenced a budget for a further three systems. That makes seven in total, all destined for installation in a post-wave work cell designed for hand assembled components.
Here at Robotas Central, we’re readying ourselves for the delights of Las Vegas! No, this is not a Hangover-style stag do or raucous gambling weekend for the boys. Instead, it’s the venue city for this year’s APEX exhibition and conference. All very civilised!
IPC’s APEX Expo runs from 25th to 27th March at the Mandalay Bay Resort & Convention Center. It is among the industry’s premier events, featuring advanced and emerging technologies in printed board design and manufacturing, electronics assembly, test and printed electronics. As you can see, it’s right up Robotas’ street. It also hosts one of the largest technical conferences in the world.
Vertu is the pioneer and leading manufacturer of luxury mobile phones. Created to complement the discerning customer’s lifestyle, Vertu offers tailored, luxury services in combination with the finest in design, engineering and manufacture. With three distinct collections – Signature, Ascent and Constellation – Vertu uses innovations in manufacturing technology with traditional craftsmanship, assembling each phone by hand at the company’s headquarters in Church Crookham, England.
Vertu required a process whereby each craftsman could accurately and efficiently build each handset, accessing the assembly instructions unique to each particular model. The craftsmen needed to be presented with exactly the right part in the right build sequence. Vertu also wanted to find a way to significantly reduce build time to meet the time demands of its customers, without compromising the quality for which the brand is renowned. Finding a solution to these challenges was key to its business. Because SIGMA has been specifically designed to assist the hand assembly of products which absolutely must be right first time, SIGMA was the perfect solution to Vertu’s challenge!
In 2006 Robotas installed the first SIGMA systems, each with touch screen monitors and barcode readers to quickly load the correct assembly program for each unique work order. Vertu has been so pleased with the benefits which the system offers their business, they now have 58 systems in operation and have plans for the installation of more systems in the future. The system also encourages operator feedback which can be verified and used to further enhance the process, thus ensuring best practice at all times.
“SIGMA ensures that all of the benefits of hand assembly are matched with unparalleled accuracy. It is the perfect synergy of technology with the excellence delivered by our craftsmen.”
Ben Newbrook – Senior Industrial Engineer
For our through-hole work, we originally had carousels but with no visual aids for our operators. We therefore had to rely on our experienced operators’ expertise and memories. Everything was a manual process, including the selection of the program for build. There were many mistakes leading to incorrectly built PCBs. Our training was based on product knowledge, which meant it could take up to three months before an operator could work effectively without supervision.
In 2006 we installed six Mascot stations which were retrofitted to Nutek conveyors to make a complete flow line system. Now the assembly programs are selected using scanners. We simply scan the product code on the job sheet and the relevant visual work instructions appear for that particular PCB, while the correct parts are offered to the operators. As soon as we switched over to using the Mascots, our errors plummeted. In fact, it reduced the incorrect builds to zero. Yes, zero, in one easy move!
Also, thanks to the on-screen visual aids and the barcode scanner implementation, our training is now based on the process, not the product, and as a consequence training time for new operators has been reduced to just two weeks.
We have been using Mascots for many years now and find them very reliable. Right from the outset, Robotas gave us great support in installing and commissioning the equipment and also explaining the Mascot programming operation. Even now, we know that if we have a problem we can simply phone up and the team will pull out all the stops to help resolve the issue.
Process Technician / Supply and Development Co-ordinator
“Prior to having our Mascot stations installed, we built all our through-hole assemblies following paper based work instructions with the component parts stored in different pots on the desk. Occasionally we’d use flip jigs, if that was possible. As soon as we switched to building our PCBs on Mascot Pushtracks our build time halved. Immediately there were fewer mistakes and the boards looked much neater.
We also find the Mascots handy when new staff members join the assembly team, or when we have people on work experience with no prior knowledge or experience in electronics. Thanks to Mascot, they can help out in a genuinely meaningful and productive way by getting involved in building PCBs with little or no training. All they do is simply follow the on screen instructions and the overhead laser. The correct parts are delivered to them at every step, so they can’t get the build wrong.”
Sophie Westrop. Internal PCB Production and Test Supervisor
Celestica are using Sigma systems to build complex products for the aerospace industry at their Toronto facility in Canada. They now have 3x Sigma systems.
” Before our Sigma purchases, we used a form of kitting process for box build where an individual would collect all the parts (screws, nuts, other hardware and electronic components) and place them in bags or tote boxes. It was a lengthy process and susceptible to errors. Overall it had a negative impact on our quality and therefore delivery to our customer.
Then we acquired our first Sigma system. Suddenly there was no need for kitting in the traditional sense since all the parts needed for assembly were located at the point of use via the motorised carousels. The Sigma system with its graphical and video instructions eliminated issues over wrong parts and quantities being used and enabled our operators to build more efficiently without defects.
We especially like the Low Bin Monitor feature on Sigma, which alerts the materials handler to replenish the bins. So no more production downtime! We quickly recognised the potential and purchased two more Sigma stations – one of which has four carousels holding 200 parts for our more complex assemblies. The Robotas support team is always efficient, flexible and very receptive to new ideas we sometimes have to help Sigma evolve to meet our new needs. I rate them eleven out of ten! “
Engineering Technical Support Analyst.
Honeywell workcell. Celestica HQ, Toronto.
Sigma offers many features to help eliminate errors and drive productivity:
- Computerised step-by-step work instructions, images and videos are displayed to the operator.
- Optional motorised carousels automatically present the correct component or tool.
- LED indicators highlight the exact storage bin location.
- Supporting documentation is easily displayed.
- Data inputs such as measurement readings can be recorded at any step.
- External inputs can conditionally alter the assembly procedure.
- Data signals can be output at any step to drive external tools or machinery.
As well as displaying written assembly instructions, Sigma provides annotated images and helpful video clips to illustrate each assembly step, completely eliminating ambiguity. In addition, other features and options further streamline the assembly operation.
It’s a straightforward process that simplifies product hand assembly to make it fast, consistent and right first time.
Three key Mascot features help to eliminate errors and drive productivity:
- Computerised step-by-step work instructions are displayed to the operator.
- Motorised carousels automatically present the correct component.
- A laser highlights the exact location on the board.
It’s an assured process that makes PCB hand assembly fast, consistent and easy.
Mascot also provides images of components, parts or subassemblies for improved process clarity, and videos to walk the operator through assembly procedures. Each Mascot station can accommodate up to 376 different components – enough capacity for the largest of boards, or for several different boards with no set up or changeover delays.
Motorised carousels present the operator with the right component at every step. The innovative eye-safe laser indicator even highlights the correct component orientation, leaving absolutely nothing to chance.
There is an efficient solution when Mascot runs low on materials. Kanban signals alert stores to notify of low stock, leaving to operator free to continue assembly uninterrupted – a further boost to lean manufacturing productivity.
Barcode verification helps validate critical parts and aids traceability. Scrap recording allows operators to log details about unusable parts. A find function searches the assembly by part number, part description or assembly step – ideal for rework and quality assurance inspection.
The ‘Need’ function issues Kanban signals to stores to notify of low stock, leaving the operator free to continue assembly uninterrupted – a further boost to lean manufacturing productivity.
‘Redline’, an intelligent feedback tool, gathers shop floor expertise to build a knowledge database that can be used to improve future assembly procedures.
Data signals can be input and logged at any assembly step. Specific data results, such as voltage, weight or dimension readings, can invoke a conditional change to the assembly procedure automatically. Operators are unaware of this step change, which avoids confusion when assembling complex structures.
Similarly, data outputs can be deployed at any assembly step. For example, to set a motorised torque screwdriver to the correct turning force for screws delivered at that process step.