23/05/2007
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Cold forming – CERATIZIT puts on pressure!
Including report on carbide insert at SFS Intec, Switzerland
Carbide products have become indispensable for cold forming. Of course steel can be tempered, but beyond a certain degree of stress its properties are simply insufficient. In the field of cold forming carbide tools from CERATIZIT give convincingly better tool life and higher dimensional accuracy.
The business unit ’Industrial Wear Parts’ of the CERATIZIT group develops, produces and supplies various carbide tools for cold forming, such as high-performance cold heading tools for the fastening technology, dies, pressed blanks, punches and drawing dies. The CERATIZIT Hitzacker site produces blanks which are subsequently finished in the customers’ own tool room while the Italian based company (in Alserio) delivers ready-for-use tools. In this way CERATIZIT customers are supplied with blanks and tools by one source only.
Cold forming – the all-rounder amongst the production methods
Cold forming is applied worldwide to manufacture the most varied products: nails, screws, pins, copper tubes, aluminium drinking bottles, Steelcord for radial tyres etc. Also, most of the metallic objects in a household are produced applying this method: handles, hinges, connectors, strips and many domestic appliances.
Cold forming is a collective name for all production methods where the form of metals or metal alloys such as copper, aluminium or brass is deformed at room temperature with high pressure, but without changing its volume, weight or the essential properties of the material. In cold forming the blank is normally formed in several stages. In this way the deformation capacity of the material is not exceeded, so material breakage is avoided.
A practical example: carbide insert at SFS Intec in Switzerland
SFS Intec in Heerbrugg, in the north-east of Switzerland has been a customer of the CERATIZIT group for more than 15 years. Today the company has more than ten production sites with over 2800 employees where it produces precision forming parts, special screws and mechanical fastening devices. In 2005 it reached a turnover of 465 million euros. For the automotive industry, for instance, SFS Intec produces special forming parts and special screws for steering systems, adjustment systems for the seats and electronic regulation systems. In the electronic industry SFS has made a name for itself with special screws for mobile phones, special screws for razors and for the mounting of PC components..
Interview with Werner Marte, head of the mould and die construction department at SFS Intec
What are the advantages of cold forming?
Marte: “Unlike cutting, cold forming does not produce any waste material. Furthermore a very good surface quality is achieved without having a finishing operation. The component’s tendency to notching is also considerably lower, no unstable transitions result, as would be the case with turning.”
What is essential in the manufacture of cold forming parts?
Marte: “Knowledge of the technology, the correct tool geometry, quality of the parts and the guarantee of customer benefit. The customer requests parts that are ready for mounting and free of faults“.
In cold forming also tools made of steel are applied. What is the proportion between tools made of steel and tools made of carbide?
Marte: “Carbide inserts are used a lot more frequently than tools made of steel, and the trend is increasing. Steel can be tempered, but above a certain level the properties of steel are no longer sufficient. Carbide tools show longer tool life and higher dimensional accuracy. Particularly in cold forming carbide is a very important material."
SFS Intec uses both blanks and finished tools from CERATIZIT. When do you buy blanks and when finished tools?
Marte: “We buy CERATIZIT blanks for making nibs and dies. Finished tools are bought when we don’t have the technology and the necessary know-how in our company. I’m referring to internal grinding and pre-sintering of complicated geometries. We also use semi-finished tools from CERATIZIT in order to accelerate our production cycle. For SFS the high quality of the carbide is decisive.”
Screw production – the production steps at SFS
The starting material for screws is supplied as a thick wire rolled up on coils. Before the deforming operation the material is uncoiled, aligned and sometimes drawn reducing it to the requested diameter (also a type of cold forming). Modern extrusion presses work on various levels so that such machines, depending on the screw, are able to produce more than 1000 pieces per minute.
Example of the production steps for a hexagonal screw:
1. Cropping the wire blank from the coil
2. Producing the top part of the screw and reduction
3. Pre-heading
4. Finish-heading of hexagon
5. Deburring
6. Producing the thread by means of the thread rolling machine
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