THE LONG AND SHORT OF IT
When is a machine tool used for longer running jobs the best choice for small lot sizes and short lead times? This manufacturer of test probes found the answer.
Posted: October 30, 2008
To listen to Dave Coe, vice president of QA Technology, Inc., a leading manufacturer of printed circuit board test probes, tell it, his customers have a simple view of the benefit his company provides. "The shorter the better as far as our customers are concerned," says Mr. Coe.
When he says short, he's referring to short lead times and small prototype lot sizes of the array of components and connectors his company engineers and manufactures. Historically, QA Technology's component manufacturing had been outsourced to a number of vendors with a variety of CNC machines. Because of the demand for quick turnaround and small lot sizes, QA Technology decided to add CNC Swiss capacity to his company, in order to fill customer requirements that outside vendors simply could not economically and reliably meet.
As a result, QA decided to purchase a Tornos Deco 7a, a Swiss turning center used by some of their current vendors and one that offered flexible turning and milling capabilities and superior cycle time-savings potential for longer running jobs. But since speed of every job was critical and the company lacked TB Deco programming skill – QA turned to PartMaker to help them bridge the gap between CAD and NC program for their Swiss turning center. They chose the SwissCAM system specifically designed for programming Swiss-type lathes and one that integrated directly to the TB-Deco operating system that controls the Deco 7a machine.
PartMaker provides the link between QA's engineering department, which designs its product using both 2D drafting and 3D solid modeling methods, and the manufacturing department that is tasked with producing the part. "The really big benefit to having this is the ability to take the solid model or even the DXF file coming out of our engineering department for the part and immediately import it and be able to view, edit it as necessary and generate accurate tool paths that are not subject to human error as they often are when you are using manual programming methods," says Coe. "After programming the part, we are able export to the TB Deco advanced environment."
The SwissCAM module is a CAD/CAM system dedicated to automating the programming of Swiss-type lathes such as the Deco 7a at QA Technology. The system generates a CNC program by allowing the user to either create or import part geometry into the system, apply tooling to the geometry by choosing a variety of cutting strategies, simulate the part cutting in a virtual 3D environment and then, generate an NC program.
This software is unique in its programming of Swiss-type lathes because its makes use of two patented technologies to do so. The first of these technologies is known as the Divide and Conquer programming strategy. This approach to programming allows the user to look at a multi-axis Swiss lathe for what it really is, a lathe with a main and sub spindle with up to nine different types of milling possibilities, including polar interpolation on the face, cylindrical milling on the diameter, Y-axis milling on the diameter, C-axis indexing and so forth.
ART TO PART
A big benefit is being able to take the solid model or even the DXF file coming out of the engineering department for the part and immediately import it and be able to view, edit it as necessary and generate accurate tool paths that are not subject to human error as they often are when using manual programming methods. After programming the part, QA exports directly to the TB Deco advanced environment.
The second of these patented technologies focuses on automating process synchronization, or the method by which operations that are running at the same time or simultaneously are handled. This Visual Synchronization approach lets a programmer quickly optimize a program graphically by choosing from a selection of pictorial diagrams that indicate the synchronized state in which he wants his machine to operate. From this, the software produces an optimized time study showing just how long the part will take to manufacture.
Once the tool paths have been defined and the process has been optimized, the user can simulate the process to check for any errors or tool collisions off line. Once the user is happy the part is running well, he chooses a post processor to generate an NC program his machine can understand.
This is where the Deco platform presents a unique challenge. A-line machines such as the Deco 7a at QA Technology are not CNC machines, they are PNC machines. This means they do not accept a standard ISO-based G-code program like other machines a CAD/CAM system would typically support. (Editor's note: Standard ISO-based G-code programming is standard on the Tornos Sigma line of machines.)
In 2004, in a unique collaboration between Tornos and the developers of PartMaker, Tornos opened TB-Deco to accept input from PartMaker via the import of a special file format called a TTFT (Tornos Text Format) file. The invention of this file format, which can be automatically generated by PartMaker and directly imported into TB-Deco, allows the software to be able to directly interface to Deco machines the way it interfaced to other CNC machines previously. To interface PartMaker and TB-Deco, the user must have the TB-Deco ADV software along with the accompanying CAM Interface module. This partnership between Tornos and PartMaker benefits many parts makers. "If it looks good in the simulation, it should look good when it comes off the machine," according to Phil Pierce, a CNC programmer at QA Technology.
Even though QA Technology is a first time Swiss user, they have found themselves using the integrated SwissCAM-TB-Deco system exactly the way the products' designers imagined. The idea behind the partnership between was to automate the programming of a part. For shorter running jobs, the user might not even make any adjustments to data imported into TB-Deco. For longer running jobs, where every fraction of a second counts, the programmer can use the unique optimization capabilities of TB-Deco to achieve the fastest possible cycle time.
Since PartMaker does the handle cranking work of creating the program and setting up a working program in TB-Deco, Mr. Pierce can use his expertise to wring additional cycle time out of the job in the TB-Deco environment, all of which is of course done on an off-line PC. On other Swiss-type lathes, additional optimization is typically done on the shop floor at the machine control, while the machine is down and not making parts.
For QA Technology, really it just comes down to how fast they can program and run the part. "For me, its all about speed," says Pierce. "It's easy for me to take a job that's come in, throw it into SwissCAM, generate a program, send it right over to Deco and optimize the program in Deco and get parts running within a day. If I had to write the whole program through Deco, it would take a lot more time. With the system we have in place, it's a very quick turnaround to have high quality parts coming off the machine."
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QA Technology, Inc., 110 Towle Farm Road, Hampton, NH 03842, 603-926-1193, Fax: 603-926-8701, www.qatech.com.
Tornos U.S., 840 Parkview Boulevard, Lombard, IL 60148, 630-812-2040, Fax: 630-812-2039,www.tornos.us.