Precision guidance shafts, guide shafts, flat guide rails

ZOLLERN semi-finished products are processed further and used in various areas of vehicle construction in:

• Injection pumps
• Throttle solenoid valves
• Injectors
• Suspension struts / shock absorbers

We implement heat treatment regulations on our own developed hardening machines with a patented hardening process. The most frequently used materials are 100Cr6 and HS 6-5-2 (HSS). The semi-finished products are tested 100 per cent on a test track

ZOLLERN supplies shafts and flat guide rails for

• Rubber and plastics machines
• Printing machines
• Woodworking machinery
• Assembly and handling technology
• Casting machinery
• Machine tools
• Straightening machines

CNC-controlled turning machines with main and counter spindles allow the complete machining of parts, including gear cutting, inside and outside. Tools for rolling highly stressed threads, up to M 140 x 4, are used for the production of rods and columns. The transitions are machined with smooth rolling tools in order to meet particularly high requirements. Special surface requirements are met by finishing with stone or tape and lap grinding to Ra =< 0.07 µm.

For linear technology, ZOLLERN supplies ready-to-install components from prefabricated semi-finished products according to customer drawings, which are characterised by flawless surfaces and excellent mechanical properties.

Customer-specific finished parts

There are many possible applications and materials of shafts and flat guide rails for construction machinery:

• Piston rods
• Damper pistons for oil / gas
• Hinge pins
• Pump pistons

Special manufacturing processes improve the properties of the chrome-plated surface while inductive hardening increases the wear resistance.

By means of CNC-controlled inductive hardening, ZOLLERN increases the wear resistance of the shafts and rails. Hardening depths of 0.5 to 8 millimetres and hardness values of up to 67 HRC can be achieved.

Hardening distortion is reduced to a minimum by targeted hardening. Short heating and austenitisation times prevent scale, edge decarburisation and residual austenite. Toughness and strength are retained in the unhardened areas. Subsequent machining is possible at any time.

Furnace hardening is a patented in-house development for demanding through-hardening with variable holding times. The integrated straightening process creates a high straightness of the hardened bars in the dimensional range from 3 to 20 mm diameter and a maximum length of 3,500 mm.

Centreless grinding is the most economical grinding variant for bar stock. The geometry is generated during this operation. ZOLLERN grinds in a dimension range from 1 to 205 mm in diameter and a length of up to 8,000 mm. Tolerances of ISO 6 are standard. If required, ISO 5 is possible.

The surface structure is optimised by polishing or belt grinding. ZOLLERN uses systems with up to five polishing stations. The desired surface is achieved in coordinated steps, up to a mean roughness value Ra < 0.15 micrometres. Polishing is also used after chrome plating.

ZOLLERN is one of the first hard chrome plating companies to produce piston rods and linear guide shafts in the manufacture lengths. With the introduction of continuous chrome plating in 1991, ZOLLERN was quick to focus on environmentally friendly processes.

The improved deposition results, especially in small dimensions of six to 30 millimetres in diameter, ensure good layer distribution and very good concentricity. The optimum coating thickness for linear guides is 10 micrometres and for piston rods 20 to 30 micrometres. Layer thicknesses up to about 50 micrometres, tolerances IT7, by request IT6.

Different machining methods are used to produce customer-specific finished parts:

• Turning, conventional
  Machinable components: Maximum length 6,300 mm, diameter 5 to 380 mm, maximum weight 2,000 kg
• CNC turning
  Machinable components: Length 10 mm to 6,280 mm, diameter 4 to 400 mm
• CNC turning with bar feeder
  Machinable components: Maximum length 8,000 mm, diameter 3 to 80 mm
• CNC milling / boring
  Machinable components: Maximum length 8,000 mm, synchronous machining 8 to 100 mm, round or flat, maximum 2,000 kg
• Chiron milling centre
  Traverse paths of X-axis 8,000 mm, Y-axis 630 mm, Z-axis 550 mm, NC swivel head, speed range 20 rpm to 12,000 rpm, NC rotary table, dividing accuracy +/- 2", face plate diameter 500 mm
• Surface grinding
  Machinable components: Maximum length 8,000 mm, height 280 mm, width 400 mm,
  grind ends at an angle, 50 x 150 mm
• High speed grinding
  HSG Studer S32, diameter 1 – 10 mm, cutting with contour grinding using the plunge-cut method