A FANUC Robot Presents Parts for Deburring

Machining castings into precision components is an increasingly tough challenge.   Global competition forces price pressures in addition to the traditional machining and handling issues.  TMF Center is an Indiana-based manufacturer of components for construction equipment and the trucking industry.  “TMF Center has a long term strategy to leverage automation to be a high quality and low cost manufacturer,” according to J D Green, Plant Manager.    

TMF Center assembled a vendor team of companies that worked to achieve the highest quality and best price for the machining and post processing of a casting.  This article discusses the planning and evolution of an advanced and flexible process that allows TMF Center to develop and manufacture tight tolerance parts and achieve aggressive cost targets.    

Prototype parts and initial machining processes were developed on stand-alone five-axis Mazak Variaxis 630 machining centers from Shelton Machinery.   As production grew, TMF Center leveraged a Mazak Palletech Flexible Manufacturing System (FMS) to minimize labor content and achieve production schedules.       

The five-axis machining center allows a three-step machining process.   The first operation (OP10) machines locating details and rough features on the casting.   The second operation (OP20) machines all of the topside surfaces.   The part is flipped for the third operation (OP30), and the final machining.  

TMF Center found a balance between features and processing time through the three machining operations.   The part requires machining from all six surfaces and many angles.   Without the five-axis CNC flexibility, part re-clamping and more machining operations would have been necessary, and part variance from unclamping and re-clamping would have increased part variability.   

The system achieved first generation machining and second-generation prototyping on the initial line.  The second generation required much more machining and a higher production volume.   This called for an additional FMS Shuttle System and additional machining centers (total of 22 machines in the plant).  

The second-generation design incorporated performance benefits and cost savings and therefore customer demands mandated a quick transition period.    Tooling refinement, hard work, and manual operations hit production goals but not customer cost goals.   Further automation was required, and the automation had to work with the existing systems.    TMF Center had the vision to install the FMS systems so it could incorporate a FANUC Robotics Toploader robot with a 26.5 meter long travel rail.    

The FANUC Robotics Toploader robot with a 70kg payload easily traverses the distance across the machining lines to deliver parts.   The robot’s six-axes tolerate any out-of-alignment or out-of-square conditions of the FMS system, and its flexible wrist is able to flip parts over between OP20 and OP30.  

Busche Engineered Tool Division provided a unique hydraulic clamping system that could couple and de-couple to the FMS pallet.   The hydraulic clamping allowed for automation and greater process repeatability than the manual nut drive system from the original FMS.   FANUC Robotics’ and Busche engineers worked together to develop an interface between the robot, the automatic clamping, and the Mazak FMS.  

FANUC Robotics engineers worked with TMF Center to define a post-machining deburring process.   A FANUC R-2000iA floor-mounted robot handles the finished parts through a range of deburring steps with a carbide deburr tool.  The deburr process focuses on larger burrs over many areas of the part.   Fine burrs are removed later in the process by a Thermal Deburr machine.  Barry Henderson, FANUC Robotics’ controls engineer, used the Remote Tool Center Point function which simplified teaching the deburr and blowout positions. 

The Thermal Deburr process is helpful because it relieves the robot from having to remove the smaller burrs.   However, it also caused complications when loose chips on the part or in the part had to be removed.  Loose chips often became dislodged and fused to the casting, creating a scrap component.

During the manual blowout stage, an operator would probe and blow out all the holes and cavities in the part.   To mimic this manual approach, FANUC Robotics and TMF Center developed a compliant air pipe, hole blowout system.   This mechanical system uses air pressure to force out the embedded chips.

Here’s how the system works:

-          Manual load and unload of a Mazak Variaxes 630 for the rough machining of locating surfaces on the raw casting (OP10).   The operator loads the part to a conveyor for the infeed to the FANUC Robotics M-710iBT.

-          The M-710iBT robot takes the OP10 part with a dual hand-tool and loads a staging station near the FMS shuttle for line 1 or line 2. 

-          The FANUC robot transfers through unload and load of OP20 and OP30 processes for the FMS shuttle.   The robot interfaces with the hydraulic clamping to automatically unload and load the parts, and it is equipped with a blow-off nozzle to blow off chips from the part and the locating surfaces on the pallet fixture. 

-          Once a part has been machined through OP30, the Toploader robot transfers the part to an outfeed conveyor.  

-          A FANUC R-2000iA robot removes the part from the outfeed conveyor, deburrs many areas on the part, probes the openings, and blasts out embedded chips.  A vision system is used to identify the machining centers that performed the OP20 and OP30 processes, and these are serialized to the part by the robot.

-          The robot places the part back onto the outfeed conveyor for manual unload and inspection prior to thermal deburr and washing operations. 

The combination of the Toploader guarding solution and the FMS loader system allows TMF Center to service or maintain any of the machines or the FMS loader while still running the balance of the system.   The system can achieve high production and machine utilization rates while supporting tool setup functions.     

This full automation solution has been installed and running since late 2005.   TMF Center is looking forward to a simple software changeover and little capital equipment changes to accommodate a new component for the 2010 green engine design. 

TMF Center had used two FANUC ARC Mate robots for flame cutting prior to the current system.   They also purchased and installed an ARC Mate welding system in 2006, and are looking forward to future robotic automation to increase their quality and productivity.  

This article is schedule to appear in Modern Machine Shop, Jan. 2008.