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Competing on the global engineering stage has always forced Encoder Products Company (EPC) to stay cutting edge in both its approach to product design and manufacturing. Based in Sagle, Idaho, EPC manufacturers premium rotary incremental and absolute encoders used for motion feedback. Employing about 150 people world wide, EPC performs all of its engineering and manufacturing in its Idaho facility. All the parts for the encoders it makes are manufactured in-house across a bank of multi-axis CNC machines including among others a number of Mori-Seiki twin turret, twin spindle lathes and a Star CNC multi-axis Swiss-type lathe.
EPC was founded 35 years ago by Bill Watt who invented a unique encoder housed in a cube. EPC has been machining the parts that go into its encoders since day one. As EPC’s product line has expanded and its design process became more sophisticated over the years, it found it needed to program faster than manual programming techniques allowed. To make the leap to a more automated method of programming, EPC standardized on PartMaker CAM Software in 2005. PartMaker is developed by PartMaker Inc. (Ft. Washington, PA), a subsidiary of Delcam plc.
“The productivity improvements we’ve seen using PartMaker have been incredible,” remarks EPC Production Manager, Todd Egland. “Using the software, we’ve decreased our machine set-up time by at least 50% by not having to tie up the machine to prove out a program.”
“For us, the software has really enhanced our ability to program a part on a PC and run it on the screen rather than having to waste spindle time running it on the machine, which was what we had to do before. Before we had the software, we would program manually off-line, get the program as far as we could and start making chips on the machine to see how the part was going to come out.”
Manual Programming vs. PartMaker: No Contest
EPC’s need to move to PartMaker from its previous manual programming approach stemmed from a number of factors in its business. As the company acquired more multi-tasking lathes, the complexity of its programming increased. Currently, EPC’s line up of multi-tasking lathes includes Mori Seiki ZL and DL twin-turret, twin spindle turn-mill centers, a Murata MT twin-turret, twin spindle turn-mill center and a Star SV-32J CNC Swiss-type lathe outfitted with a gang slide, turret and sub spindle. All of these machines are capable of performing extensive milling operations in addition to simultaneous machining operations across their multiple spindles.
While EPC’s machining capacity grew in both numbers of machines and complexity, EPC’s engineering department was becoming more sophisticated in its approach to product development. Part of this increase in engineering sophistication meant migrating from 2D design techniques to solid modeling design using Solidworks. The move into a 3D design environment coupled with growing customer demand for more aesthetically appealing encoders increased the geometric complexity of the parts EPC had to machine. As the geometric complexity of features with blended radii and other complex geometric forms grew, Egland found his programmers having to spend more time with engineering to calculate the geometry need to plot cutter paths. Once the code was developed, a great deal of time was being spent at the machine proving out the program before a part could be placed into production.
“The amount of programming time that is saved depends a lot on the complexity of the part to program. We have noticed that if there are arcs that blend into other arcs and blending corners for smooth appearance, PartMaker can make the machine tool path faster than we can figure out the points to make a trig function from to try and plot the tool path,” says Egland. “It is no contest that PartMaker can generate code faster than anyone trying to do it manually.”
Dropping the Part Complete
Now, with PartMaker, EPC programmers are able to interface to the design engineering department by directly importing solid models into PartMaker from Solidworks, creating a seamless data bridge between engineering and manufacturing.
Once the model is imported, PartMaker goes to work. For EPC’s application, PartMaker represents a unique programming solution because the software is able to program all of the machines on the shop floor. At the heart of the software, are two patented technologies for automating the programming of multi-axis Turn-Mill centers and CNC Swiss-types lathes.
The first of these patented technologies is a ‘divide and conquer’ programming technique for handling parts with a number of turned and milled features being performed in single setup. PartMaker breaks a complex part into a set of faces. The faces can be planar or rotational, and each can contain various machined features such as holes or interpolated pockets. A specific machining function such as turning, polar milling or cylinder milling is assigned to each face. A dedicated window, referred to as a face window, contains a workspace for the graphical representation of the face features. This approach allows the programmer to program the part in the same way a machine looks at the part, which makes creating the tool paths for a part with a number of turned and milled features a very intuitive process.
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For EPC, the ease with which PartMaker handles turning and milling operations on one part not only means programming their parts faster, but also allow EPC to improve their appearance by allowing its programmers to debur parts right on the machine, thus alleviating costly and time consuming secondary operations and manual deburring.
“The software has helped us by quickly allowing us to run a chamfering tool around sharp edges alleviating having to do deburring by hand, off the machine. By the time we pull the part off the machine, after letting PartMaker do the deburring process, it’s an absolute finished piece that needs no secondary finishing or hand touching,” notes Egland. “PartMaker makes a good looking part a great looking part.”
Knowledge is Power
PartMaker is based on a concept called Knowledge Based Machining which means the software is able to make recommendations about machining techniques such as feeds and speeds for various materials like aluminum or stainless steel based on the tool being used. The user is also able to teach the software about their own experience with respect to tooling and materials by creating tool libraries and customizing the material database as they program parts with the software. Thus, the more the software is used, the “smarter” it gets about EPC’s application.
“PartMaker has enabled us to program parts and see what times will be. It makes programs that allows parts to run more efficiently and economically by determining speeds and feeds whether running 303 stainless or 360 brass and with the tooling applied to it, it will pick up our spindle speeds and feed rates automatically,” notes Egland.
Once tool paths are created, the user generates a Process Table, which presents an exact cycle time for each process. The Process Table allows the programmer to easily synchronize operations being performed simultaneously by multiple tool, employing the second of PartMaker’s patented technologies, a system called “Visual Synchronization.” Here, the programmer chooses the type of synchronization strategy being performed from graphical diagrams. For example, if he wants to cut with one tool on the main spindle while cutting with another at the same time on the sub spindle, he merely chooses a diagram corresponding to this type of synchronization by just pointing and clicking.
These visual synchronization strategies are applied automatically to every process on the part. Because the software knows the architecture of the machine being programmed, it checks that the synchronization strategies used by the programmer will actually work. If the programmer tries to synchronize operations in a manner the machine cannot handle, the software indicates where the error has occurred.
When synchronization has been completed, the software displays a balanced cycle time, showing how much time is being spent on the main spindle, how much time is being spent on the sub-spindle and the total machining time, taking into account all concurrent operations. At this point, the programmer can see if additional cycle time reduction opportunities exist and make the changes accordingly, right at a PC. The ability to generate accurate cycle time estimates off-line is critical to EPC’s production planning.
“With business getting more competitive, it’s critical we have a cost associated with each of our components. With PartMaker we are able to establish that cost without having to run the through the machine,” says Egland.
Setup Time Impact
Once a part is programmed in PartMaker, the user can perform a vivid 3D simulation of the machining process right on their PC to see if there any errors on the part or collisions on the machine. This simulation helps to greatly reduce machine set-up time, because it allows programmers to detect problems off-line before they occur at the machine.
“Setup times are greatly reduced especially on new parts. What used to take 4 hours or more on the setup of a new part, can be reduced to less than an hour due to the ability to process the part without actually using the machine tool by doing it on a PC off line. PartMaker gives us actual run times and shows if there will be any interference with the machine tool,” says Egland.
NC Code: Right the First Time
Of course seeing the part on screen is great, but none of that would matter if the software did not generate accurate NC programs. The final link in the production chain for EPC is the robust post processors used to generate code for each of their machines.
“If you have CAM system that doesn’t give you the NC output you are looking for, then you have to go back to the old way of manually programming which is exasperating and that’s not what the software should be doing for you. It should be doing what PartMaker does: It makes the code that’s right the first time to make the part,” states Egland.
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