Super long tool new concept

The camshaft aspect ratio is clearly problematic during machining. And processing all the files from the cylinder head end face is also a challenge. However, KOMET Group has verified that its ultra-long knives also have excellent application facts - BMW's newly produced four-cylinder engine motorcycle has successfully used special gun reamer.

It is often said that the quality of a car is related to its length. If this is the case, the length of the stretch from the front to the rear is important, then the K1200 S and R MUSCLE motorcycles produced by BMW will definitely run very well. By using a cylinder bank to tilt forward 55°, the engineer found the best compromise between the wheel base and the center of gravity, improving the revolutionary technical design of the car level. For example, 16 valves are controlled by a camshaft, which minimizes friction. The reaming tool produced by KOMET Group validates the availability of long tools when machining camshaft reaming on the cylinder head. In this case, the 5th hole with a 12HT drilled hole expands by a distance of approximately 310mm. A similar tool concept has been applied when machining camshaft holes. Tool developers have also introduced this concept of length into the continuous machining of five 25F7 reamings.

The BMW cylinder head machining production line has a total of 69 precision tools for the cylinder head cutting operation. Each of these tools has been specially designed and designed to meet the machine manufacturer's overall machining strategy. However, at present, the finishing operation of the camshaft hole is still a big challenge. Just as the tools responsible for the BMW Berlin engine have to meet the demanding requirements of concentricity and verticality, the size of the bore is also very precise, and the holes can only be machined from one side, and of course many unfavorable harsh machining conditions make the problem difficult. More arduous, intermittent cutting during machining and changes in the wall thickness of the part can also cause dimensional deviations.

In most cases, finishing is done using a multi-blade reamer made by Dihart. The first two holes are finished by a short guide reamer, and the rear three holes are finished with an extra long gun reamer. What is common is that the pre-machined edge of the step reamer corrects the original positional offset of the aperture. In addition, the guide strip can serve to support the tool when the lower hole is finely adjusted. The central coolant prevents damage to the finished holes and produces a smooth, precisely matched hole.

When reaming the camshaft, the reamer cutter uses a replaceable reamer. The PCD diamond cutting edge is welded to the tip and the end face contact of the short cone ensures high precision repeat positioning tolerances. When replacing an alternative reamer, there is no need to make any adjustments to it. The advantage of the alternative reamer blade is that it can be implemented very quickly during installation and commissioning, thus avoiding possible errors. This technology will of course be used during most of the cylinder head installation operations, and the Dihart tool life will achieve the desired results. The gun reamer is mounted and adjusted on the spindle of the machining center. The axial runout is controlled within 3 μm, and the maximum error deviation on the angular coordinates is 3 μm.

The high precision of the tool can also be confirmed by the life of the tool – the life of the reamer head is up to 8000 camshaft holes. For the finishing of the camshaft bore, the replacement of the reamer head may result in additional cost savings. The wear of the guide block is much less than the wear of the reamer, so the reamer is often replaced several times before the shank needs to be replaced. Mr. Fürstenau said: “We will perform 100% row tolerance inspection on the machine. In addition, the machining cylinders before and after the tool change must have full production quality control, they will be fully measured. This means any line. The deviation of the bit tolerance will be identified at the initial stage, so that the reliability of our production is guaranteed."

The processing quality of the cylinder head is the primary factor that ultimately affects the level of performance of the vehicle. Just like the new standard of the latest 1200 motorcycle set, this standard is not only about performance, but also its excellent internal power. Therefore, KOMET tools have also set a new level in the drilling of camshafts, and also validated the new concept of ultra-long high-precision tools.

Screw

Jiangsu Dingtian Stainless Steel Products Co., Ltd. , https://www.dingtiancasting.com