When Jasper (Indiana) Engines & Transmissions remanufactures a family of engines or transmissions, the process starts with the new product development division researching popular powertrain products, resolving inherent design issues and determining how to improve a product's longevity. The process continues with core disassembly; thorough cleaning; machining the block, heads, crankshaft, camshaft and connecting rods; and installation of new, qualified or improved components. The final stage is product-specific testing.

The company's Wernsing Road facility, which is one of four, remanufactures up to 120 gasoline engines daily. To keep remanufacturing costs competitive, the goal is to qualify and reclaim as many parts from the original engine as possible. Jasper Engines & Transmissions reports that when it rejects core components, it replaces them with core parts and castings from the same engine family or new ones.

When remanufacturing an overhead cam cylinder head, the production department first oversizes cylinder head cam bores and either builds up camshaft journals or uses a cam-bearing shell in place of the material removed from the bores. Unfortunately, the time required to align camshaft housing bores for specific cylinder heads and meet the company's production requirements proved to be an ongoing challenge.

Initially, production used right-angle heads on knee mill-type machines and short tools that fit between the cam-bearing caps, the company reported. The one-bore-at-a-time method was unreliable at maintaining concentricity from one bore to the next. Production then modified a gundrilling machine and applied a 762-mm-long (30") single-point line boring and reaming tool. The downside was that this method required manually loading the long, heavy tools — a strenuous task for operators that eventually damaged the machine's spindle because of excessive wear.

In addition, the manually intensive process produced more rejects than acceptable parts, so Jasper Engines & Transmissions' production needs still were not being met.

The company determined that it needed a horizontal toolchanger. See automatic toolchanger." title="CNC machine tool capable of drilling, reaming, tapping, milling and boring. Normally comes with an automatic toolchanger. See automatic toolchanger." aria-label="Glossary: machining center">machining center that could handle the long boring and reaming tools. Already possessing machines built by Mazak Corp. in Florence, Kentucky, including the VC-500A/2PC, VCN-570C and VCN-530C vertical turning centers, as well as the QT-250MSY, QTN-250MSY and QTU-200 multitaskers, Jasper Engines & Transmissions chose Mazak's HCN-6800 HMC with a two-pallet changer, 80-tool storage capacity and an automatic toolchanger that accommodates 762-mm-long tools, said Garrett Robinson, CNC specialist at Jasper Engines & Transmissions.

Also, the machine's Mazatrol SmoothG CNC, working in tandem with probing macros that he developed, reportedly significantly reduces the risk of error in part loading and actual machining and frees operators for more value-added tasks.

"Prior to the HCN-6800," Robinson said, "we had to use up to five different processes for oversizing cam bores, and the previous machine lacked the necessary accuracy and speed for the tooling we wanted to use. The HCN-6800 not only allows us to use that tooling but also gives us much better surface finishes and more precise and concentric bores, all at a much faster production level."

He said the machine also enables Jasper Engines & Transmissions to bore any size overhead camshaft, or OHC, head.

Having a fourth-axis table on the HMC creates a lot of options, including the ability to run up to four parts at a time on two tombstone fixtures, Robinson said. To further automate OHC head machining, his probing routines remove any operator guesswork from identifying and positioning fixtures.

He explained that during a probing routine, the HMC checks for a part in all or any of the four fixture positions. Once the HMC detects a part, the machine runs another touch probe macro to determine which families of heads are clamped on the tombstone. Then the machine selects the appropriate program for the head types, determines how much stock is in the bore and compensates for it by adjusting the speeds and feeds. Because Jasper Engines & Transmissions does not run batches and may have many random variations of the heads that it processes on the machine, this capability it especially beneficial.

"We need machines that are versatile and can handle OHC heads for multiple engine types, along with all their included variations that may be in production at any given time," Robinson said. "The HCN-6800 allows us to process more parts faster, so our other remanufacturing departments no longer wait for OHC heads."

With the machine's control, Jasper Engines & Transmissions can tune the machine for vibration during the cut, adding to the HMC's ability to consistently hold tight tolerances, said Taylor Friend, a QC captain at the company.

"The HCN-6800 is definitely making my job easier in terms of quality control, mainly because of its high accuracy and repeatability," he said. "Some of the tolerances we have to hold well below 0.001" (0.0254 mm), and our previous machines produced a lot of rejected parts."

For more information from Mazak about Jasper Engines & Transmissions, view a video presentation cteplus.delivr.com/25cy5