Universal cylindrical grinding machine

The Kellenberger Varia universal cylindrical grinding machine offers a large work space, long machine table, and distance between centers of up to 63" (1,600mm).

Hydrostatic guideways provide damping, stick-slip-free operation, high rigidity, and a constant machine temperature, improving surface quality and process and operation reliability without friction loss and wear. Direct drives on the rotary axes offer high positioning speeds and accuracy. Drives move the longitudinal and cross slides at speeds of up to 787ipm (20m/min) at an axis resolution of 10nm. The hydrostatic B-axis is equipped with a direct drive, allowing the revolving wheelhead to rotate 3x faster and with position precision of <1 arc second.

The Varia is available with distances between centers of 39.4" or 63" (1,000mm or 1,600mm), and center heights of 7.8", 9.9", or 11.8" (200mm/250mm/300mm). Travel on the X- and Z-axis is extended. The task defines the position of the wheelhead within the machine, which ensures optimum distance and dressing conditions. More than 30 wheelhead variations with external and internal grinding spindles permit the right application-specific grinding configuration.

Heidenhain GRINDplus640 controls provide user-guided ISO programming with selective help images and collision monitoring. The controls allow faster working speeds and high precision. Axis control in the nano range offers high profiling and track accuracy for contour grinding. Optionally, the Varia can be equipped with the Fanuc 31i control. Remote maintenance with integrated IT security connects to the customer network via VPN tunnel or mobile communication.

Hardinge Group Inc.

www.hardingeus.com

Multisensor dimensional measurement system

The large measurement volume SmartScope Quest 800 multisensor dimensional measurement system offers a 790mm x 815mm x 250mm X-Y-Z measurement volume and an available 300mm or 400mm extended Z-axis to measure large parts or large arrays of smaller fixtured parts. For measurement stability, the Quest 800 optics/sensor head is mounted on a granite bridge over the worktable and moves only in the X- and Z-axis, while the worktable moves underneath in the Y-axis. A 10:1 TeleStar telecentric zoom lens offers accurate video metrology. The unit is multisensor-capable with available touch trigger probe, SP25 continuous-contact scanning probe with PH10 motorized probe head, on-axis TeleStar Plus interferometric TTL laser or off-axis DRS laser, and micro-probes to measure fragile parts or extremely small part features.

The system is available with QVI’s Zone3 CAD-based 3D metrology software with a kinematic model that simulates the machine, part, fixtures, and measuring sensor in real time. Integrated geometric dimensioning and tolerancing functionality and visual validation of measurement intent speed the measurement process. Zone3 supports simultaneous use of multiple sensors, including multiple lasers, making appropriate tools available for complex measurement tasks.

Optical Gaging Products (OGP)

www.ogpnet.com

Cutting tools for continuous tool path machining

The Pow ·R ·Path IP series of cutting tools are designed to maximize high-efficiency machining (HEM) methods. Taking advantage of continuous tool paths to get maximum performance out of every tool, the Pow ·R ·Path IPT7 series and Pow ·R ·Path IPC series feature 7-flute configurations. IP series tools are made with a stronger, larger-diameter core for straighter walls in deep cuts and superior strength for longer continuous cutting at HEM’s high feed rates. Pow ·R ·Path IPC7 and IPC9 series (7- or 9-flute styles) add the special chip management system (CMS) for reliable chip evacuation even in tough alloys.

IMCO Carbide Tool Inc.

www.imcousa.com

Could a cost-effective metal additive manufacturing technology be developed to speed adoption by U.S. industry? That question prompted America Makes – the national accelerator for additive manufacturing and 3D printing – to issue a project call to find out.

The answer may come in a proposal that adds a laser-powered 3D printer to a 20-year-old 3-axis machining center.

America Makes is funding development partners Optomec, a privately-held supplier of additive manufacturing systems; MachMotion, a systems integrator with expertise in CNC controls; and TechSolve, a not-for-profit manufacturing consulting service. Optomec has fitted one of its laser engineered net-shaping (LENS) powder-fed metal 3D print engines to a 1990s-vintage 3-axis vertical machining center. MachMotion has added the controller, drives, wiring, software, and operator console so the upgraded CNC machine can perform both additive and subtractive processes on the same part. Mark Huffman, machining systems engineer, project engineer, and program director at TechSolve Inc., is in charge of validating the hybrid system.

The medium-size, 3-axis milling machine requires the addition of a hood to accommodate the 1kW laser on a vertical stage, protective glass, four powder nozzles, and a system to ventilate the argon gas that blankets the workpiece during sintering.

Huffman wants to learn how easy the hybrid machine is to use, if the parts produced are viable, and how having both technologies in the same environment affects the machine tool.

“How does the metal powder affect the machine? Does it cause maintenance issues? What are the issues? Are they negligible or critical,” Huffman asks.

Another focus is testing the accuracy of MachMotion’s CAM system and dual-process compatibility with the conversational programming controls. For the additive tests, Huffman is using 316 stainless steel because the powder is readily available, similar across several suppliers, and relatively inexpensive. The material is built up on a part in free space – powder and laser are delivered simultaneously – and the excess powder falls away. In other tests, powder has been collected and recycled, reducing waste.

Is metal deposition on a hybrid as accurate as on a standalone LENS system? “That’s one of things we’re testing,” Huffman says. “We can make a melt pool in different sizes depending on the focal length of the laser and where you focus it on the powder.” The layers produced in early testing were 0.012" thick. “We could make it thicker or thinner if we push it a bit more.”

The laser then retracts to protect it from chips, and the machine uses the same codes and control for subtractive machining. So far, researchers have used dry machining, but the plan is to study the effects using flood coolant.

Is the hybrid system ready for widespread adoption? No, more testing needs to be done. Huffman says the hybrid is at manufacturing readiness level (MRL) 6 – fully functional in a laboratory – but the goal is MRL 7, ready to be used in a production environment.

“We are making parts and some features but not production parts in repeatable runs at this point,” he adds.

Currently, researchers are testing the machine for a part repair using 316 stainless steel powder. “The test builds are complete, so the next steps are to machine our test pieces to gather data on surface finish, material hardness, and machining forces,” Huffman says.

Huffman hopes to see the hybrid technology save time by adding metal to parts and machining it to spec; to repair and restore damaged or worn parts; and to add wear surfaces to parts using stainless steels, titanium, and superalloys.

The technology is not limited to 3-axis machines, Huffman says. Adapting any 5-axis machine to a hybrid additive/subtractive machine is theoretically possible, noting, “with a vertical machining center, gravity helps deliver powder to the substrate.”

TechSolve Inc.

www.techsolve.org

Optomec Inc.

www.optomec.com

MachMotion

www.machmotion.com

America Makes

www.americamakes.us

About the author: Eric Brothers is senior editor of AM&D and can be reached at ebrothers@gie.net or 216.393.0228. 

Sharp-eyed readers may have noticed the past several months that we’ve added maintenance, repair, and overhaul to Aerospace Manufacturing and Design’s front page: “Dedicated to the Design, Manufacturing, and MRO of Aircraft and Aerospace Components.” This really isn’t news – we’ve long included articles on MRO topics – it just recognizes that many of our readers in the aerospace supply chain already perform work in that market segment, such as repairing turbine blades or manufacturing aftermarket parts.

It logically follows that with record numbers of airliners being produced, MRO spending will increase as those airliners enter service during the next decade. A forecast on page 54 expects the global MRO market to grow to more than $100 billion by 2025, with North America’s share between $17 billion and $21 billion. Engine maintenance’s market share is anticipated to grow to nearly half of that spend. That prediction should encourage anyone fearful that the 12,700 airplane order backlog now reported by commercial aircraft manufacturing’s duopoly won’t provide enough business to suppliers of jet engines, airframe components, and flight systems for the next decade or so. It should be noted that backlog does not include contracts from regional and business aircraft producers or a reviving defense sector.

Other manufacturing markets face a possible slowdown after 2016 – automobile sales are likely to peak next year. And beleaguered domestic oil and gas production is facing a long standstill. Thankfully, aerospace has a comfortable cushion of orders now and for years to come. Even if half were to disappear, there would still be a substantial backlog. (For more, read the 2016 forecast beginning on page 44.)

While a strong U.S. dollar adds headwinds to exports, it also means imported goods – including machine tools – can cost less. The Federal Reserve Board is still cautious about raising its prime rate beyond the one-quarter percentage point it decreed last December, so borrowing money remains cheap. These facts may make now the best time to invest in greater capacity, more automation, or better productivity.

Still need more reasons to start shopping? Before Congress adjourned last year, it passed a law benefiting manufacturers with a permanent research-and-development tax credit and a permanent Section 179 small-business expensing allowance up to $500,000 for new and used equipment purchases (up to $2 million) ordered and placed in service in a tax year. Also included in the bill is a five-year extension of 50% bonus depreciation effective with the 2015 tax year. This applies only to new equipment, but there is no cap on the amount that can be depreciated.

The $1.8 trillion tax and spending compromise measure funds the federal government through the 2016 fiscal year – eliminating sequestration anxiety from short-term continuing resolutions – and it restores more than 50 expired tax provisions, 22 of them permanently. Amber Thomas, vice president of advocacy for AMT – The Association For Manufacturing Technology, hails the bill’s enactment as “a major victory” that should give manufacturing a boost heading into this year. AMT explains the provisions of Section 179 at http://goo.gl/Z1eyOq. – Eric

Cell requirements

Here are a few questions to ask when considering an automation cell. You may want it to unload and load the machine tool, but do you want something designed to load only one type of part or something flexible enough to handle other parts as well? A system handling a family of parts could keep the change-over to a minimum, or the cell could be designed to handle almost anything within a certain size range – but flexibility tends to cost more money. How often and what kind of change-over are you expecting? Automation can be configured to allow some components to be automatically changed, but this is more expensive than manually changing components over. How much infeed capacity would you like the cell to accommodate? A lot of capacity is great, but too much capacity can take up a lot of space and be a waste. How much room do you have for the cell? Do you plan on running the cell with the robot all the time or will the machine be used manually without the robot for periods of time?

The robot

The main component in the automation cell tends to be the robot, the device that provides most of the required motions. Automation robots are divided into Cartesian- and articulating-style. Cartesian (X/Y) style robots are basically grippers on two rails and are often seen on turning centers. One rail brings the robot over the machine and one rail brings the robot down into the machine to the spindle. Occasionally, a third axis is used to allow the robot better access to the spindle when overhead obstacles, such as the door configuration, limit direct access to the spindle. Quite often, Cartesian robots are developed and sold as a semi-standard option by the machine tool company and are purchased as part of a package along with the machine tool. These Cartesian robots tend to be less costly than the articulating arms, but they are not as flexible. They can only move back/forth and up/down along the rails. If all you are doing is loading/unloading, then this may be a good solution.

Articulating robots are the 6-axis arms traditionally thought of as industrial robots. Very flexible, they can reach into some hard-to-reach places and perform many other tasks beyond basic loading/unloading. These robots can be mounted on the floor, on a wall, or upside down, depending on the requirements of the cell.

It is important to make sure you purchase a robot that is designed for the intended application. A robot designed for use in a clean laboratory would not be suitable for the coolant-dripping and chip-covered environments prevalent in most machine tools. To determine if your robot is suitable for the environment, robot parts will have an ingress protection (IP) rating. These ratings are a two-digit number with the first digit being the solid particle protection and the second digit being the liquid protection. For example, a rating of IP63 is dust tight and will handle dripping water, where a rating of IP66 is also dust-tight but will allow water/liquids spraying directed at the robot.

Industrial robots are sized by reach and payload. Maximum robot payload is normally stated from a specific point on the center of the faceplate on the robot. Everything that gets attached to the end of the robot needs to be included as part of the payload. This includes not only the components to be loaded and unloaded, but also the grippers or other part-picking devices that are mounted to the end of the robot.

The distance that the robot grippers are mounted from the face of the robot can affect the payload. Most robotics companies have payload calculators which allow you to evaluate the details of the EOAT for compliance to the maximum robot payload. While there is no substitute to using a formal payload calculator program, a good rule of thumb when using basic EOAT is to assume half of the robot payload for the parts and half for the grippers/mounting plates.

The reach of the robot is another important consideration, it will need to reach both the machine and the infeed/outfeed system.

End-of-arm tooling

EOAT is the generic term for the tooling secured to the robot arm that performs the tasks the robot needs to do. In machine tool load/unload, pneumatic grippers typically grab the parts. Suction cups and/or magnetics are sometimes used, but the vast majority of machine tool load/unload EOAT’s are pneumatic grippers. Similar to the robots, make sure you are using good industrial-grade grippers designed for the appropriate environment.

How many grippers are needed on the EOAT? When loading a single workholding position such as one chuck on a lathe or one vise on a mill, the typical answer is two – one to grab the finished machine part and remove it from the workholding and one that has the incoming raw blank and loads it into the now-open workholding. Using two grippers to unload and load with one trip into the machine reduces the load/unload time but increases the weight on the end of the robot. For example, if you are loading two workholding positions, the first operation in one vise and second operation in the second vise, the number of grippers will increase even further. It is important to factor this in when calculating EOAT weight and robot payload.

The next question is the type of gripper. One look at a gripper catalog and the choices will seem overwhelming, however, once you focus on the grippers designed for the machine tool loading/unloading task, the choices are usually much more manageable. When grabbing square parts, rectangle parts, or parts with opposing flat surfaces, a two-jaw parallel close gripper is the gripper of choice. When grabbing round or hex parts, three-jaw centric close grippers are preferred. Four-jaw grippers lend themselves to picking parts out of a tray. Three-jaw grippers tend to have a jaw out of place when picking from a tray or a place where parts are presented in rows and columns. A four-jaw gripper will place a jaw in each corner, eliminating the interference. Grippers come in many different sizes and are rated by gripping force and stroke. Try to select the smallest gripper that will do the job to keep the robot EOAT weight down.

Most gripper companies offer finger blanks that can be machined and/or modified for gripping the parts, similar to what is done with chuck or vise jaws. Unfortunately, these fingers cannot be machined in place like a vise or chuck jaw, so a simple fixture can be used to hold the fingers in proper place for machining. When machining a set of fingers, machine them to allow the best possible opening for easier picking of incoming blanks. A chamfer or radius will also help facilitate better picking. Incoming parts are not always as consistent. The extra opening and chamfers simply makes it easier to accommodate the unplanned differences.

Methods Machine Tools Inc.

www.methodsmachine.com

Part 2, will appear in the March 2016 issue, and focuses on infeed and outfeed systems, probably the most important, difficult decision to make when designing an automated cell.