Honing of cylinder bores on SPECHT

For the integration of honing technology on the SPECHT series an adjusting spindle with electromechanical drawbar has been developed. With this system, high precision can be achieved in many other tools besides honing by defined adjustments (blade compensation). With honing on the HMC, MAG offers a full-fledged alternative to the conventional honing machine, which
includes all regulation and control algorithms for honing (including the pneumatic in-process measurement). This both in the single spindle SPECHT, as well as on the two-spindle SPECHT DUO. The advantages of honing technology on the same machining center are
multi-layered. Due to the permanent detection of the actual oversize after fine boring the subsequent honing can be significantly shortened. This results in lower investment costs of lines with honing machining centers over a conventional honing machine, whereby the savings for investment and operation can be as high as 20%. Further advantages of the honing solutions on the HMC include the redundancy through parallel processing, scalability at production start-up and easy reusability of the machine when changing products. Thus, a honing machining center can later be reused for other tasks apart from honing, if required. The processing results are impressive as well: Cilindricities < 5 μm at cylinder bores are easily and safely accessible after honing. Due to the rigid HSK100 interface in combination with the fine boring in one clamping the position and location of the cylinder bores after honing are extremely precise as well.

SPECHT 600 L with draw-bar spindle for honing : SPECHT 600 single spindle machine for machining included honing

SPECHT 600 L with draw-bar spindle for honing : SPECHT 600 single spindle machine for machining included honing

It comes as no surprise that customers from the automotive industry have successfully been using the honing on SPECHT in serial production for approximately 2 years. In the past, MAG’s focus lay on honing of cylinder and crankshaft bores. By now, MAG is also looking for applications outside of the cylinder block and intends to offer interesting and new solutions there, too.

Coating of cylinder bores

The thermal coating of cylinder running surfaces is already introduced into some series applications at various automobile manufacturers. The reasons for these coatings are numerous and usually include the following points:

  • reducted friction
  • increased durability
  • resistance to corrosion caused by poor fuel quality
  • Better heat transfer, essential for small turbocharged engines
  • Downsizing: Reduction of engine block construction space leads to weight reduction
SPECHT 500 DUO+ with Pallet changer : SPECHT 500 Duo+ double spindle machine with axis compensation and pallet changer

SPECHT 500 DUO+ with Pallet changer : SPECHT 500 Duo+ double spindle machine with axis compensation and pallet

To improve the efficiency and robustness of the entire process chain MAG is cooperating with the STURM group from Salching, Bavaria. MAG especially contributes the expertise of machining and automation while STURM covers the topics of inspection, coating and cleaning. Thus, the entire process chain can be offered from a single source (turn-key) and the individual process steps can optimally and flexibly be adjusted according to the individual requirements of the customer. The necessary surface activation prior to coating can be done mechanically on a SPECHT HMC. Alternatively, the partners can also offer high-pressure water jetting. For greatest efficiency, the mechanical roughening is preferred and continuously refined. After coating, the “finish machining” of the cylinder bores can take place on the MAG machining center either by fine boring or rough honing. For economic reasons, the fine boring is expected to be the preferred solution in the future. However, development efforts are still needed in order to get the tool life in an acceptable range. Of course, the finish honing of coated cylinder bores also is possible on the SPECHT. With these advantages in the areas of efficiency, robustness and flexibility MAG and STURM offer a process chain that so far is unique on the market.

The two-spindle machining center SPECHT 500 DUO+ is developed especially for the supply industry. Full flexibility with five-axis machining with a pallet changer for runtime parallel loading and highest productivity through reduced chip-to-chip times by dynamic magazine discs do not leave any demand of machining out of consideration. An ergonomic, also runtime parallel loadable chain magazine with large capacity meets the needs of a processing center in an ideal fashion.

Source MAG