Sub-contractor and mould maker Norjon Engineers has more than doubled the size of its factory to 14,000ft
2, following a 60% increase in turnover in 2011, compared with the previous year. Moreover, growth continued at around 25% in the first half of 2012. The new, modern facility on the Quay West Business Centre in Gosport was officially opened earlier this year by the MP for Gosport, Caroline Dinenage.
Five years ago, owner and managing director Kevin Fox bought his first two five-axis Hermle machining centres, both C 20 Us. Featuring a working envelope of 600 x 450 x 450mm, they are used to produce aluminium and brass thermo-forming moulds that are supplied to the food industry for the production of plastic packaging such as yoghurt pots, food trays and disposable cups and lids.
Mr Fox said: “Surface finish is important, as good cosmetic appearance is a prerequisite for plastic packaging in the consumer industry. The finish off the Hermle machines is superb, so we do not have to hand-polish the moulds after machining.”
Rapids of 45m/min and an 18,000rev/min spindle ensure short cycle times, while the robust rotary table and trunnion arrangement, with its bearings set directly into the mineral casting that forms the bed, ensures that tight tolerances can be easily held — even during the full five-axis machining of deep features with steep draught angles. It was not long before Mr Fox started transferring sub-contract jobs from three-axis equipment to the C 20 Us to take advantage of the more-efficient production in fewer set-ups that results from automatically positioning and clamping the extra two axes.
Much of the work at Gosport requires the machining of aluminium-bronze and duplex stainless steel to produce seals for a customer in marine propulsion. The yachting, printing and power-generating industries are other regular users of Norjon’s services. The company is also a supplier to the motor-sport, aerospace and medical industries, while new business has been won recently supplying manufacturers of sub-sea and petrochemical equipment. Some tolerances are extremely tight — down to 2µm in total — although 5µm on some oil and gas parts is routinely held.
Larger machines
As component sizes started to increase, Mr Fox required larger five-axis machines; in 2011, he opted for two Hermle C 40 U models with travels of 850 x 700 x 500mm. One of these machines has an 18,000rev/min spindle, which is ideally suited to the high proportion of aluminium machined at Gosport; the other has a 10,000rev/min high-torque spindle for the ‘heavier’ cutting of steels and harder materials.
About half the programs for the Heidenhain controls on the Hermle machines — and some other machining centres on site — is carried out on the shopfloor. Preparing programs for the other 50% of jobs — generally the more-complex parts requiring four- and five-axis machining — is performed using seats of Delcam and Alphacam (these are also used to import customers data in most formats).
Norjon, which has a workforce of 30 and holds BS EN ISO 9001:2000 quality approval, has invested heavily in a variety of machines in the recent past. In addition to the Hermle machining centres, the company has acquired a co-ordinate measuring machine (this works alongside traditional metrology equipment in a dedicated inspection department), two new mill-turn lathes, other prismatic machining plant and a Matrix tool-vending machine from Taegutec. It also operates wire-cut EDM machines, as well as machines for cylindrical and surface grinding, manual milling, manual turning, gear cutting and laser engraving.
In conclusion, Mr Fox said: “Our company motto is ‘nothing is so good that it can not be made better’. That is why we strive for constant improvement in everything we do. Our policy is to look to the top end of the machine tool market and buy on spec, without having any particular work in mind for any given machine or bothering about payback times. It is an approach that has served us well. We have 10-times the turnover we had 10 years ago, and we progressed from a single shift to 24hr working in May last year.”