• Shenoy Engg Private Limited

Case Study: Twin Station 8 axes CNC SPM

Shenoy Engineering Pvt Ltd, a Bangalore-based special purpose machine SPM manufacturer, has designed and manufactured a twin station, 8 axes, CNC controlled, stock turning SPM for a large scale component manufacturing industry. This SPM is designed to take the load off 8 high end turning centres.

 

Problems faced by the customer:

• The cast job of the customer has a stock removal of around 8 mm in the bore and face
• The customer cannot reduce the stock during casting stage, as the job profile is such that any reduction in stock at one point would eat up into the finished area at another point, leaving no option, but to retain huge, machining stock on all the walls of the components
• On a CNC turning centre, the cycle time required is 10 minutes for rough turning of 7 mm stock and the rest 1 mm would be finish-turned in a cycle time of 2 minutes. Total cycle time is about 12 minutes
• It is noted that the turning centres is not suitable for heavy cuts beyond 3 mm which was leading to the increase in the cycle time, and
• Customer approached the company to manufacture a CNC turning SPM, which could cut 7-8 mm in one single go.

 

The Solution

• The company offered the customer a machine with the following features and specs:
• A twin station concept – one station to bore and face the front end of the job, the other to bore and face the rear end of the job
• Each station has 2 sets of compound slides with servo driven cross and longitudinal axes. One set of compound slide does facing while the other will be used to bore
• Both the facing and boring slides will work simultaneously to reduce the cycle time
• Slides made of male, heavy-duty, extra rigid, case hardened guideway strips and female turcite lining, and
• Many innovative design features for reducing the cost, without diluting the stock removal capabilities within the specified time.

 

Sequence of operation:

• Manually load cast job onto left hand chuck and on the auto-cycle button
• Job gets clamped automatically and head stock starts rotating
• Machining of the face and ID of the front end of the job takes place
• While machining on LH station is going on, operator loads an ID machined job on RH station, and
• On the auto-cycle button and rear side machining of the job takes place in the RH station.

 

Cycle Time: Every 75 seconds, one rough turned component is achieved.

 

Conclusion:

• The customer is now getting a rough turned component at the rate of 1 piece/75 seconds, compared to the earlier 1 piece/10 minutes, i.e., a cycle time reduction of 87.5%
• A comparatively less accurate, highly affordable, stock turning CNC SPM is expected to result in elimination of 8 high end, accurate, expensive CNC turning centres, which are hitherto used for rough turning operations
• Reduction in man power – 8 CNC operators along with 8 turning centres are now available for more gainful work
• Increased output, and
• After rough turning in the machine, finish turning is carried out on CNC tuning centres, thereby cutting down the whole cycle time from 1 piece/12 minutes to 1 piece/3.25 minutes, i.e., a cycle time reduction of around 73%.