FANUC has developed a new M-800iA/60 high-precision, high-speed laser processing robot with a new servo control system that increases the robot’s path accuracy for exacting applications.  This capability makes it suitable for laser trimming of hot-stamped components. This robot can replace expensive multiaxis CNC machines used for that application.

The operator reported that the enhanced drill bits provided better bit life, rate-of-penetration, and drilling efficiency than standard heavily reinforced tungsten-carbide heel and gauge structure or the diamond-coated ovoid inserts that were then commercially available and tested in the same well.

“The biggest challenge for stampers continues to be getting the maximum output of lines,” KUKA’s Jurczyszyn said. “This requires fast, linear, and stable part transfer from press to press—with high availability and low maintenance time. If the automation is not properly sized for the duty cycle, premature failure will occur.”

More durable PCD gauge inserts were developed for use in the hardest and most abrasive applications, based on a failure-analysis study, modeling work, and laboratory testing. The resulting gauge inserts have up to 50% PCD, well suited for the hardest and most abrasive applications, and provide up to 330% more diamond volume than the previous version.

These inserts employ features related to the manufacturing processes or interface geometry for improved mechanical properties.8-12

The laboratory test results were confirmed with bits on a full-scale downhole pressurized simulator and numerous field tests. Making the insert aggressive with a sharpened shear cutting edge and allowing it to actively engage and shear cut the hole wall was by far the better bit arrangement.17 18 24

In more abrasive applications, it was obvious that carbide trimmer elements were inadequate and diamond-enhanced trimmers would be required to maximize the benefits of the novel cutting structure.

ABB Robotics’ RobotStudio AR viewer provides a quick way of visualizing where and how robotic automation can fit into a process from a smartphone or tablet. Photo courtesy of ABB Robotics

The average gauge wear was negligible compared to the heavy wear on the conventional bits. For the enhanced gauge bits, average rate-of-penetration dropped 10%, from 2.2 to 2.0 m/hr, as a result of wear to the overall carbide cutting structure being heavy from their substantially longer distance drilled in the abrasive formations.

An early press start prevents unnecessary delay when exiting and closing the press. Encoders within the press allow the loading robot to follow parts distancing to optimize the unloading robot’s actions and prevent time lost from signal exchanging.

The petroleum industry's use of diamond enhanced inserts continues to grow in importance as the search for oil and gas pushes operators into more difficult environments, with a more demanding well paths, and higher requirements for staying-on-bottom to reduce trip time in high cost environments.25

Drill bit manufacturers have substantially improved polycrystalline diamond (PCD) cutters and drag bit designs since their introduction in 1972. PCD drill bits are now approaching the rolling cone tungsten carbide insert (TCI) market in terms of revenue size and have surpassed it in terms of economic impact on the drilling industry.1 2

In addition, to help eliminate the risk of potential interference between the robots and the press, the robot’s design was revised to reduce the working area in the robot’s third axis from 120 degrees to 80 degrees.

Many manufacturing methods and styles of diamond-enhanced inserts were explored. Laboratory tests of individual inserts, measuring the relative forces and insert durability, resulted in an insert with a sharpened, shear cutting edge providing the lowest forces and best durability.

Laboratory tests have shown that the force to remove the rock was reduced by a factor of 40% for the new PCD shear-cutting gauge inserts, relative to conventional carbide inserts (Fig. 4).18

The new design uses fewer conventional heel row inserts, a secondary cutting structure called a trimmer row adjacent the heel area, and gauge inserts with a clearance or relief angle to reduce drag. This yielded an efficient method of removing material in the corner of the borehole or at the borehole wall-borehole bottom juncture (Fig. 5 and 6).

Typically, the operator required fewer bits to drill the interval, reducing cost in mature fields, with marginal reserves.

In the very hard and abrasive formations of East Texas, the rig cost is relatively low, and the cost-to-benefit value of high-cost features like diamond enhancements is more difficult to justify.

Subsequent laboratory testing of other styles of diamond-coated gauge inserts used commercially have proven them to be durable but inefficient in removing rock ribs because they crush the rock with their rounded unaggressive shapes.

Many robots and lasers can process a part simultaneously, making them well-suited for a large part such as a door ring, Jurczyszyn added.

The North American operators obtained performance improvements by maintaining full-gauge hole that reduced reaming time-to-bottom in the under-gauged hole, avoided damage to the next-bit from reaming, increased rate-of-penetration, length of run, and bit reliability.20

As bearing and seal packages improved and bit life extended, carbide inserts were no longer adequate for the harder and more abrasive formations. Early attempts to employ diamond as a passive wear-resistant element met with limited success because the diamond layer was prone to cracking and chipping.

A major research and development project focused on increasing the efficiency of cutting structures through a better understanding of the drilling mechanics in the heel-gauge area of the bit. The project resulted in a novel cutting structure that can drill about 20% faster and is at least as durable as conventional designs.22 15

Laboratory tests reveal that the drilling mechanics on the heel and gauge of a rolling cone bit have a significant shear-cutting component. Failing rock by shear is more efficient than by crushing, but most cutting materials cannot withstand forces generated in the shearing process as rock strength increases.

The authorsDan Scott is group leader, hard materials research, for Hughes Christensen, and he has served in a variety of technical and managerial positions during his 31 years there. Scott is a registered professional engineer, a member of ASTM, IADC, SPE, and is an ASM fellow. He holds a BS degree in metallurgical engineering from the University of Missouri.

Marcus Skeem is a staff scientist in hard materials research and development at Hughes Christensen. He started with Christensen Diamond Products in 1974. He holds an MS degree in chemical engineering from Ohio's Airforce Institute of Technology.

By using specially designed diamond-enhanced carbide inserts, roller-cone drill bits can take advantage of this shear-cutting component to increase drilling efficiency by maintaining hole gauge and increasing bit life.

“Many stamping companies are looking to implement some form of robotic automation but are unsure of where to start,” Roda said. “RobotStudio is an intuitive digital tool that helps simplify the installation and use of robots.”

FANUC’s Sharpe agreed. “Many stampers are challenged with the ability to meet higher throughput demands and interpress exchange rates with more difficult environmental impacts to worker safety such as larger and more complex stampings that are difficult to handle.”

“The robot is designed to eliminate the time, cost, and disruption associated with repurposing dedicated press-tending machines. It can be quickly adapted and reprogrammed to handle new products without the need for re-engineering,” Roda said. “Its 3.18-meter reach and a rotating seventh axis that allows parts to be reoriented between consecutive stamping operations mean that one robot can access different presses and dies.”

“Our customers are telling us that they want the line to run faster; however, this causes issues with press wear and tear and racking pileups at the end of line,” Jurczyszyn said. “There comes a point where the operators at the end of the line cannot keep up.”

FANUC developed PressSync software that couples an encoder to the press, allowing the robot to determine the appropriate timing to enter and close the press. The software eliminates the need for an expert programmer to tweak the anticipation timing to achieve optimal throughput, according to Sharpe.

The Type 4 and 5 bits were identical except for the type of gauge protection. The operator found that average bit life increased about 50% for the diamond gauge protected bits, with the distance drilled increasing from 49.0 to 74.2 m/bit and run time increasing from 22.5 to 36.8 hr/bit.

Diamond-enhanced gauge protection increased bit life, footage drilled, and rate-of-penetration, with reduced reaming of the following bit. As a result, the gauge-protected bits were cost effective in most applications.

In an early trial of the diamond enhanced shear-cutting gauge in the Southern North Sea in the Carboniferous Namurian formation, one well required eight standard bits with conventional carbide protection. Of these, only three were pulled in gauge.

Operators adapt the shear cutting elements as a primary cutting insert for the heel row with good success in some applications.

“We have seen struggles to keep pace as well as with the physical demands of heavy parts,” said DieBotics’ Launiere. “Employee safety is compromised every time an employee has to touch the material.”

Complex Parts Handling. In addition to providing a more dynamic linear axis, tilting, and shifting axes, the handling systems have been optimized to handle more complex components. “Our Cobra handling systems have special carbon carriers that are flat and light, but still are constructed so that they are stable enough to support the materials handled in these applications,” Jurczyszyn said.

The oil and gas drilling industry has successfully developed and commercially applied shear-cutting diamond enhanced elements for a wide variety of roller-cone bit applications and markets globally, ranging from the high-cost offshore North Sea to low-cost North American land operations.

A predecessor of what is now TotalFinaElf AS reported the first field trials of a diamond-enhanced active shear-cutting gauge feature in 17 1/2-in. roller-cone bits. The trials were in an exploration well in the overthrust area of southern Italy.19

Laser Trimming, Transfer for Hot Stamping. “Hot stamping for lightweighting steels brings an entirely new set of challenges that are different than traditional stamping and requires die and process adjustments for each,” Jurczyszyn said.

They subsequently targeted the gauge trimmer insert for diamond enhancement, for more severe drilling conditions, given the improved drill bit's rapid commercial success and the chisel shape of the new insert.

A built-in, user-programmable control using Boolean logic can handle the material handling as well as run additional tasks. “For example, an inspection camera at the end of the process can be monitored so defects are caught in real time. In-die sensors can be monitored and in-die mechanisms actuated using this feature.

The viewer allows stampers to test and refine options before they are implemented. New product lines can be installed faster and ramped up to full speed without surprises during commissioning, Roda said.

FANUC is developing new and intuitive user interfaces and applications to make startup and programming easier for the user, according to Sharpe.

In hard and abrasive formations, it is more common to use second-generation ultra thick table gauge inserts, with or without a diamond enhanced ovoid or similar insert in the heel and inner rows.

Special-purpose. Special-purpose robots can better address specific needs, according to Launiere. “We are identifying specific needs and creating special-purpose automation to fill a need not easily serviced with a general robot.”

Blank Separation. More efficient methods of separating and controlling blanks during transfer operations have been developed, Jurczyszyn said.

An operator in a series of development wells in Western Egypt found the diamond enhanced shear-cutting gauge was superior to bits with conventional carbide gauge protection.

Further developments and design improvements led US operators to adapt the bits into some very demanding, hard, and abrasive but very cost-sensitive applications on North American land rigs, as in East Texas.

Operators choose a particular package based on the cost and benefits of the diamond enhanced features to reducing the overall well drilling cost, the demands of the well profile, and the daily cost of the drilling rig.

Prior technology tungsten-carbide inserts removed the ribs by a crushing and grinding process, which often resulted in heavily worn inserts producing excessive frictional heat and detritus that damage the seal located near the bit gauge.

The second area of the roller cone contributing to the bit's ability to drill a full-gauge hole is the heel row. While studying drilling mechanics to determine how to cut gauge better, increase bit efficiency, and maintain full-hole diameter, engineers developed a chisel shaped shear-cutting gauge trimmer (Fig. 1).

After studying cutting mechanics of roller-cone bits in the corner of the borehole, engineers developed and applied several cutting structure and gauge area design improvements. They took advantage of more efficient shear-cutting drilling mechanics and adopted these designs to diamond-enhanced inserts, having features of PCD cutters.13-17

In many medium-to-hard applications, operators may use more conventionally shaped diamond enhanced inserts such as ovoid, conical, and blunt chisel shapes, which drill by crushing.

The robots can be equipped with tool storage on the line, he continued. “The tools are stored in such a way as to be available to the robot during die change. One way to have tool storage on the line is for the destack robot to use a universal tool.”

According to FANUC, the latest technology gives robots the capability to use 3D vision to adapt to loading and unloading press blanks or the flexibility to transfer stamped components. Photo courtesy of FANUC

These advances in robotic automation depend on intelligent technology software to manage all parts of the system, synchronizing their actions to maximize output and optimize production, Jurczyszyn said. This synchronization is especially important with servo presses. “Our customers are telling us that servo presses are becoming the norm,” he said. Servo press and automation synchronization software packages continue to be optimized.

Operators widely employed the bits up through Type 3 class of TCI bits, or IADC 437 (based on International Association of Drilling Contractors' bit classification tables), in soft-to-medium formations with high abrasive content in the high-cost offshore North Sea environment.

ABB recently launched its IRB 760PT flexible press-tending robot with 25% faster cycle times than linear press robots, according to ABB’s Roda.

The PCD gauge inserts became a technical and commercial success in a short time and were readily adapted to conventional bits.

The decision on whether to use shear cutting elements, the crushing elements, and the rows they are used in are dictated by cost and benefits of the feature, a customer's preference, and the various proprietary positions of each manufacturer.

Combining robotic systems with sophisticated sensors in vision systems enables them to quickly identify and easily adapt to deviations in part positions before loading the part in the press line, KUKA’s Jurczyszyn said.

The shearing face of the insert is the long chamfer that engages the formation, rather than the actual insert face (Fig. 3).

Other obstacles to increased output are that the materials and part sizes vary greatly. Large variances between the smallest part and the largest part, and multiple stacks on the pallet with nonferrous blanks and laser welded blanks, can causes problems.

Advances in robot technology for stamping applications include more intuitive user interfaces to simplify programming and use, 3D vision systems, improved sensing capabilities, and automatic tool changing. Other advances are improved speeds and the ability for one robot to access different presses and dies. In addition, intelligent technology software synchronizes actions and simulation programs for optimizing preinstallation.

Generally the type and amount of diamond enhancements is determined for each application and is most likely to be as much as required, but no more.

The application of diamond in rolling cone bits runs the gamut from only heel and gauge rows to a fully diamond enhanced cutting structure.

For stamping manufacturers concerned about employee safety, an increasing skills gap, and pressure to meet higher throughput demand, robots may come to the rescue, according to KUKA Vice President Matt Jurczyszyn; DieBotics President Tim Launiere; FANUC Laser Business Development Manager Mike Sharpe; and ABB Robotics Global Product Manager-Press Automation Toni Roda.

The former Union Pacific Resources Co., now part of Anadarko Petroleum Corp., however, demonstrated the benefit of shear cutting diamond-enhanced gauge protection for roller-cone bits, in the Travis Peak and Cotton Valley formations, over a period of several months.20

The rendering shows a patented robotic walking beam transfer with two patented parallel-arm robots that can automatically load and unload the stamping process. The process lends itself to any elongated workpiece that requires postprocessing, including stamped blanks, tubes, roll formed sections, and aluminum extrusions.  Image courtesy of DieBotics

To maximize the roller-cone bit performance in soft-to-medium abrasive formations and to best utilize the benefits of the shear cutting technology on roller-cone bits, diamond gauge and diamond trimmers are combined on the same bit.

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The press-linking software brings several improvements, Sharpe said. A servo-controlled handling system enables robots to adjust press velocity so they can operate without the time-consuming stopping and re-accelerating in front of the press.

Modified for E-vehicles, Alternative Materials. The increased adoption of electric vehicles has prompted a shift from mild steel toward lighter-weight materials like aluminum, high-strength steels (HSS), and ultrahigh-strength steels (UHSS), Jurczyszyn said. This means that the handling equipment must be modified to work with each of the different materials, such as by the use of nonmagnetic destackers and double-blank detectors for aluminum.

Kate Bachman is a contributing editor for The FABRICATOR editor. Bachman has more than 20 years of experience as a writer and editor in the manufacturing and other industries.

The press-tending robot’s servo tilting modules and two servo side shifting modules help handle large and medium-sized panels and special processes such as part reorientation, tilting (±30 degrees), and part separation (±300 mm).

ABB’s StampWare includes a graphical programming wizard that decreases the time needed to train the operator and robot programmer and enables the robot system to be up and running quickly, Roda said.

Automation for Nesting. The drive to reduce material usage in production is pushing the need to nest blanks, DieBotics’ Launiere said. “The nested blanks do not lend themselves to progressive die carrying techniques. Therefore, automation is required. The automation could be as simple as a pneumatic shuttle for simple parts to full 3-axis transfer systems,” he said.

One development used improved tungsten carbide grades and shapes and innovative mechanical face seals on a journal bearing. The second used innovative diamond-enhanced carbide inserts in conventional journal and elastomer-sealed bearings.

The authors wish to thank the PCD manufacturers for their support in the early days of the effort to develop shear-cutting elements for rolling cone bits. We would also like to thank the management of Hughes Christensen for permission to publish this paper.

They have an ultra-thick layer of PCD and a long chamfer of more than 0.050 in., reducing chances of the carbide interface from contacting the borehole wall and greatly increasing the length of the shear cutting face.21

“Using our robotic walking beam transfer and two additional parallel-arm robots, the stamping process can be loaded and unloaded automatically. The process lends itself to any elongated workpiece that requires postprocessing, including stamped blanks.” The postprocessing could be stamping, machining, welding, seam locating and positioning, and inspection, Launiere added.

Sharpe said that the latest technology gives robots the capability to use 3D vision to adapt to loading/unloading press blanks or the flexibility to transfer stamped components into a laser cell. Robotic automation can be augmented by improved sensing capabilities, enabling robots to pick a stacked or accordion stack of stamped parts. “This capability reduces operator fatigue and the requirement for lift devices for large stamped components such as automotive door rings.”

Various authors have shown that the gauge holding ability of roller-cone bits, designed with a maximum number of wear resistant tungsten-carbide heel and gauge inserts, reduces contact stress and wear rate.3 4 This in turn improves bit life in many abrasive applications.

First is the gauge row of inserts which function to maintain a full-gauge hole and to protect the bearing and seal package next to the area (Fig. 1). Historically, bit manufacturers used hard-cemented carbide grade with 6-10% cobalt, for the gauge inserts.

With better bit life and gauge holding performance, the operator saved in the number of bits and thus bit trips in a high rig cost environment.

The new design also adds strength in critical areas susceptible to fracturing. Improved cutting characteristics lower forces on the gauge inserts, with 33% lower tangential force and 20% lower normal force than the old version, in laboratory tests under identical conditions simulating the scraping action on the gauge of the bit.

The ABB press-tending robot is enabled for fast automatic tool change, which can be performed in both the interpress floor area and in the bolster with the crossbar embarked together with the die, according to Roda.

The improved bit performance, reduced number of bits and trips, along with other drilling technology improvements resulted in a cost reduction of over 20%/well, allowing a major field redevelopment to proceed.

While these improvements increased gauge durability and bit life, they resulted in a heavily reinforced cutting structure that drilled with the same crushing process shown to be inefficient.

Engineers usually judge the cost and benefits of these solutions based on the merits of the technology, the nature of the formation and drilling plan, and the performance required for the particular application. Steerability may be a factor determining the application of diamond-enhanced inserts.

The app overlays the model into the real-life production environment. Users can scale it to full size and rotate it through a variety of angles to achieve the best result and can watch the model in action. A timeline feature makes it possible to check the cycle time, then go to a certain point in the animation to find ways of enhancing performance or pinpointing a potential problem.

Diamond-enhanced inserts, with the same general size and shape as the tungsten-carbide counterparts on roller-cone bits, increase rate-of-penetration, bit life, bearing reliability, and gauge holding ability by reducing the cutting structure wear.5-7

Emily Wilkins, founder of Marketing Metal, helps job shops, machine shops, metal fabricators, custom equipment builders, and other...

Laboratory and field tests confirm that these are more efficient, aggressive, faster, and at least as durable as conventional insert designs.18-24

After a slow start, several bit manufacturers are now using diamond inserts in high technology roller-cone applications worldwide as a well established, performance-enhancing feature.

From material and design improvements of the last decade, however, the oil and gas drilling industry has successfully and economically applied shear cutting PCD elements and conventional diamond enhanced crushing style inserts to rolling cone bits.

For over a decade, roller-cone bit manufacturers have been successfully using PCD-enhanced ovoid shaped inserts to increase footage while drilling medium-to-hard and abrasive formations, as well as to improve bit OD protection in many directional applications.

The Fabricator is North America's leading magazine for the metal forming and fabricating industry. The magazine delivers the news, technical articles, and case histories that enable fabricators to do their jobs more efficiently. The Fabricator has served the industry since 1970.

The development and application of PCD-enhanced inserts that mimicked the shape of the conventional tungsten-carbide inserts have also improved wear resistance and bit performance.

Two alternative developments in roller-cone bits in the late 1980s led to significant improvement in overall durability of the cutting structure and bit performance.

Furthermore, a high degree of flexibility is needed to drive as many parts as possible onto one line or separate them equally across several lines, he added.

From the laboratory study of drilling mechanics, engineers developed PCD coated shear-cutting gauge inserts that shear away rock ribs left between the heel row inserts (Fig. 2).13

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KUKA’s automatic tool change can be verified through simulation, and if required, additional motions for the robot such as floor-mounted and ceiling-mounted transfer can be verified that way as well, Jurczyszyn said.

On a close offset through the same interval with the same style of bits except for the diamond-enhanced shear cutting gauge, five enhanced bits were required, and four were pulled in gauge.

This hole section encountered hard and abrasive quartzitic sandstone containing traces of pyrite and chert with interbedded hydratable shales.

High-speed stamping robots for press-to-press operations are coming to market to match hard automation throughput. At the same time, some OEMs are moving from robots to hard automation to run tandem lines at 16 SPM, Jurczyszyn said.

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Augmented Reality. ABB’s new RobotStudio AR viewer provides a quick way of visualizing where and how robotic automation can fit into a process using a smartphone or tablet. The viewer, part of the company’s PC-based RobotStudio offline programming software, can be used to test a model created in the software, enabling stampers to get an idea of the size and scale of a robot or robot cell and how it can be deployed on a factory floor to fit around existing production equipment.