Contents
Departments Editor’s letter News and people New products
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THE RIGHT ABRASIVE
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A RECIPE FOR SUCCESS
Features
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Focus on Fabtech
FABTECH preview Get a sneak peek of the products and services that will be showcased at the industry’s big show in Chicago Robotics
Teaching robots to weld A new technology reduces the time and expertise required for programming robotic welding Safety & Maintenance
Protective investments Dedicated software streamlines the task of performing preventative maintenance on sophisticated welding equipment Filler Metals
Weathering industrial wear Superior wear resistance and freedom-to-choose welding positions result in reduced operating costs Systems & Equipment
The complete package With welding systems designed and engineered to work together, users earn more benefits Grinding & Abrasives
The right abrasive Determining the best abrasive for post-processing weld grinding starts by understanding the family of abrasive products Welding Management
A recipe for success Documenting welding procedures and the benefits that come from format and foregoing the prequalification option
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Grinding & Abrasives
THE RIGHT ABRASIVE Determining the best abrasive for post-processing weld grinding starts by understanding the family of abrasive products || by ROBERT J. MCNAMEE, applications engineer, Norton/Saint-Gobain Abrasives || Photos courtesy of Norton|Saint-Gobain
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Grinding & Abrasives
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easoned welders and metalworkers know that welding encompasses more than just laying the bead to adjoin the metal pieces to create the final product. After the weld is finished, a post-processing step is typically required.
Norton Blaze R980P flap discs provide a good balance of fast cut and extended product life.
The Norton Blaze F980 fiber discs are a good choice for hard-togrind materials and alloys, such as stainless steel, inconel, titanium and super alloys.
The type of post-processing varies, depending on the customer requirements. Most of the time, a right-angle grinder mounted with an abrasive product is involved. Several abrasive product families are available, and within those families are variations in wheel hardness grit size, disc or wheel shape, backing material and more. Knowing what will work best for a given situation is often determined by trial and error. When focusing on the abrasive product families, there are four to choose from: • Bonded abrasive thin wheels (grinding wheels) • Coated abrasive fiber discs • Coated abrasive flap discs • Non-woven abrasive discs
Various differences Flap discs come in three configurations, including type 27, which is ideal for blending and standard work.
Norton’s Type 29 or conical flap discs are typically used for aggressive cutting.
Understanding the make-up and differences among each product family helps in the decision-making process. Bonded abrasive thin wheels, or grinding wheels, are made up of two main components: bond and abrasive. The powder-like bond and abrasive are mixed, pressed in a mold and then baked to make a rigid wheel. Changing the quantity or type of bond or abrasive affects the performance of the grinding wheel accordingly. More bond creates a harder wheel and improves the product’s lifespan, while less bond creates a softer wheel and produces a freer cutting action in the grind zone. Coarser grit abrasive improves the cut rate as well as life, while finer grit abrasive produces a better surface finish and requires less pressure. Fiber discs are a coated abrasive made up of a thin backing material
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Grinding & Abrasives
coated with two layers of a resin. Between these two layers of resin are the abrasive grains, which are exposed and visibly protrude from the disc. The same principles apply as with coarser and finer grit abrasives in grinding wheels, but the abrasive grains have a more dramatic effect on the weld due to this high exposure. Grain types are best matched to the material being ground. The backing material plays a role in the cutting action and product lifespan as well. A thicker and more rigid backing improves life and cut rate, while a thinner and more flexible backing conforms more to the work and produces better surfaces finishes. These guidelines also apply when choosing a hard or soft back-up pad. Flap discs are overlapped pieces of coated abrasive arranged around the outer rim of a hub and adhered with strong glue. The overlapping method allows for more abrasive material to be mounted on the hub and improves disc life while keep-
ing the benefits of the higher grain exposure. Like the fiber disc, the grain types and grit sizes can be changed according to the cut rate and surface finish requirements. Normally these products are available in three configurations: • High density for more flaps and improved life • Type 27 for blending and standard work • Type 29 or conical for more aggressive cutting Non-woven abrasive discs are composed of fibrous material where the abrasive is bonded to the fibers by a resin. This random assortment of grain and fiber gives the disc a compliant cutting action as it conforms to the point of contact more readily. The result is a better surface finish or lower surface roughness average (Ra). Coarser grit non-wovens, while not as aggressive as fiber discs, flap discs or grinding wheels, can still provide an aggressive cut that may be sufficient for the application.
Example of a small of <1/2â&#x20AC;? width and minimal height.
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Grinding & Abrasives
Best application scenarios Each of these abrasive product families has a place in the post-processing of a weld. Now that each family has been defined, here are some application examples where they would be most useful. Bonded abrasive (grinding wheels)
thin
wheels
• Welds larger than ½ in. wide by ½ in. high – use 5-in. diameter or larger to reduce the number of wheel changes needed • Welds smaller than ½-in. wide by ½-in. high – use 5-in. diameter or smaller to reduce the weight and improve ease of use for smaller welds • Frequent abrasive product changes are not practical – working in areas that are secluded or where there are limitations on how many tools the welder can bring, such as scaffolding • Cutting action is aggressive, such as interior/exterior corner welds
An example of a heavy weld showing the height that is well suited for grinding wheels and coarse grit fiber discs.
• Rigid wheel allows for control at the point of contact to avoid grinding into non-grind areas • Surface finish is not critical Coated abrasive fiber discs • Cut rate is the primary concern • Ability to change discs readily • Overhead work where the weight of the grinder is important • Less pressure required to grind – reduces fatigue
• Confined spaces where grinding wheel breakage could pose more of a risk • Blending the weld to the parent material without overgrinding • Small work areas where a small angle grinder is the tool of choice Coated abrasive flap discs • Product life and cut rate combination important • Conformability to the weld to blend into the parent material where grinding on either side of the weld is allowable • Confined spaces where grinding wheel breakage could pose more of a risk • Forgiving cutting action – avoid large gouges • Better surface finish than a grinding wheel or fiber disc, grit for grit • Overhead work where the weight of the grinder is important • Removing weld splatter without overgrinding – 50 grit or finer
Non-woven abrasive discs • Small welds ¼-in. wide by ¼-in. high where overgrinding is a concern, such as thin-walled sheet metal • Cleaning up discoloration • Cleaning up weld splatter • Difficult to reach welds – fillet welds that require clean up • Decorative surface finish requirements While this list does not account for every weld grinding scenario, it provides a starting point to determine the best abrasive product family for the application. With some experimentation and support from a local abrasive supplier, an effective grinding solution is well within reach.
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Robotics
TEACHING ROBOTS TO WELD A new technology reduces the time and expertise required for programming robotic welding. || by ABBE MILLER, editor-in-chief || Photos courtesy of YASKAWA MOTOMAN
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anufacturers breathed a sigh of relief when robotics improved to the point where they could be included on the shop floor. However, it wasn’t long ago that without an experienced robot programmer on the team, smaller shops didn’t have the resources to program robots to execute welds. Even if a small shop
had an experienced robot programmer on the team, the outcome wouldn’t be worth the investment. The best results for utilizing robots in the welding environment were found with big companies that produced large quantities of products manufactured with highly repetitive welding steps. These | TEACHING ROBOTS TO WELD
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Robotics
organizations had the budget to purchase the robots and also had one or more full-time programmers on board to finesse the hardware and software so they ran smoothly and efficiently. Smaller, lower-volume operations didn’t see the value in adopting robotic technology because programming the robot to do the welds took as much time as manually welding the products. Things have changed.
Enter Motoman The robotic welding landscape improved drastically with the introduction of Kinetiq Teaching. Developed for Yaskawa Motoman by third party Robotiq, this technology utilizes a simplified programming technique that makes robotic welding a reality for smaller, lower volume shops. Glen Ford, product marketing manager at Motoman, notes surveys of potential robotic technology users gave the company insights into concerns within the industry, especially with regard to the number of qualified programmers in the field today. “While specialized training could address part of the issue,” Ford says, “the need to quickly change
History of robotics in industry Many innovative engineers and companies played an integral part in getting robotic welding technology where it is today, including Motoman. Here is a brief timeline that include milestones marking significant events in the history of robotics in industry:
| 1954 | – George Devol coins the term “universal automation” after he designs the first programmable robot.
| 1962 | – General Motors introduces
the first industrial robots in its New Jersey automobile factory for spot welding and extracted die-casting.
| 1973 | – KUKA, a German robotics
company, develops the first industrial robot with six electromechanically driven axes.
| 1974 | – First arc-welding robot used
to fabricate motorcycle frames in Japan for Kawasaki.
| 1974 | – Vicarm Inc. markets a robotic arm controlled by a minicomputer. The arm performs small parts assembly utilizing feedback from touch and pressure sensors.
| 1975 | – Hitachi develops the first
sensor-based arc-welding robot equipped with microprocessors and gap sensors to correct arc-welding path.
| 1977 | – Motoman introduces the L10,
the company’s first robot, which has five axes and a maximum workload of 10 kg.
| 1979 | – Nachi develops the first
motor-driven robots for spot welding.
| 1980 | – The industrial robot industry
begins to explode with new companies and technologies entering the market every month.
| 1981 | – Takeo Kanade builds the direct-drive robotic arm, the first of its kind to have motors installed directly into the joints of the arm. The technology makes robotics faster and more accurate.
| 1988 | – Motoman introduces the ERC control system, which can control up to 12 axes, more than any other controller at this time.
| 1994 | – Motoman introduces the MRC control system, which can control up to 21 axes and synchronize the motions of two robots.
| 1998 | – Motoman introduces the UP series, which has a simpler robotic arm that is more readily accessible for maintenance and repair.
| 2004 | – Motoman introduces an improved robotic control system (NX100) offering control of four robots, up to 38 axes.
| 2006 | – Motoman develops a robotic arm with cables hidden inside, improving freedom of movement.
| 2007 | – Motoman launches a super speed arc-welding robot, reducing cycle times by 15 percent and making it the fastest welding robot in existence.
| 2013 | – Motoman develops Kinetiq Teaching, drastically reducing the time and expertise required for programming robotic movement.
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Robotics
Yaskawaâ&#x20AC;&#x2122;s compact ArcWorld C-50 features an MA1400 robot equipped with Kinetiq Teaching.
Associate Engineer Chris Anderson demonstrates the ease of hand guiding a robot with Kinetiq Teaching.
jobs for short runs or small batches still needed to be addressed.” Kinetiq Teaching simplifies the programming of industrial robots to do welding so that the need for special training and skills is greatly reduced. Furthermore, the technology provides an intuitive teaching motion that is faster than traditional robot programming methods. Ford notes the American Welding Society’s statistic that says 40 percent of manufacturing companies have declined new contracts due to insufficient availability of skilled workers – another reason why Kinetiq Teaching is so valuable to companies of all sizes today. “This shortage of skilled workers, and programmers especially,” Ford says, “drove the interface design so that benefits could be realized by both novice and expert users.”
The teaching interface As the slightly customized name would imply, Kinetiq Teaching involves manipulating the robot’s movements by hand to the appropriate points where welds need to be made. The location of these points is automatically entered into the system with the touch of an icon
on a handheld interface, thereby kinetically “teaching” the system to go where the robotic arm was moved by hand to the correct points. This simplifies the process through which the robot is “taught” the steps required in repetitive welding scenarios, thus reducing the time it takes to set up the welding steps. “We have seen Kinetiq Teaching programming setup times that are 20 percent to 50 percent faster than traditional manual programming method times,” Ford says. “With just a few hours of training and use, operators begin to reduce their programming times. One recent training session saw a new user reduce the programming time by 6 percent on the first job and by the third job had reduced it by 41 percent.” Utilizing software and a touchscreen interface, the cumbersome task of programming is now as simple as moving the robotic arm to the correct position and touching icons on the screen. Once the points are recorded, the welder looks over the trajectory of the movements and makes modifications if needed. With Kinetiq Teaching, there is no need to be proficient in algorithms and robot programming language to control the robotic movements. | TEACHING ROBOTS TO WELD
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Using Kinetiq Teaching, an operator guides the robot by hand and then easily programs the weld points.
A user-friendly touch-screen menu is now all that stands between robotic welding and the welder???. There is also no need for the operator to understand the concepts of linear or circular interpolation because the software behind the technology automatically reduces the number of programmed points for the most appropriate and efficient trajectory. Most vendors create their own language to control their robots. Motoman is no different, yet regardless of what language a programmer speaks, anyone with welding knowledge can utilize Kinetiq Teaching. Motoman’s language is
called Inform, and it can be edited manually, which gives users access to all the features available in the Yaskawa controllers. Furthermore, saved programs can be edited or modified with Kinetiq Teaching. Operators using Kinetiq Teaching are able to save between 20 and 50 percent on robot programming time, which offers an excellent return on investment, even for smaller shops with low-volume production. “Complexity of the job to be programmed does contribute to the level of improvement,” Ford notes, “but both novice and expert programmers can achieve significant savings.”
Perks of Kinetiq Teaching It’s intuitive • Avoid the missteps that occur in traditional robotic welding with fast manual positioning • Change the torch angle easily – by hand • Robotic arms move at proportional speeds • Active motion keys allow the robot to be jogged manually
It’s easy to use • Familiar smartphone app-style icons on the color touch screen are used to enter motion and weld instructions • Verify programming with or without welding • Easily edit sequences • Graphic interface is easy to use, requiring little training
It has multiple configurations • Retrofit the Kinetiq Teaching sensor on existing MA1400 robots • Benzel or Tregaskiss air-cooled torches are two popular brands that integrate with Motoman’s solution • Sensor mounts are low-profile, located between the torch and the flange on the robotic arm
It’s digitally powerful • Export to Inform, Motoman’s programming language, to save programmed points while gaining detailed I/O and sensor instructions. Insert comments in the Inform job • All exported jobs can be saved for later use • Edit weld parameters and speeds with ease • Label all comments displayed in Arc Start files
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