Tag Archive for Internal grinding

TEMSA enhances its production capacity with another new Studer CT730

Studer CT730

TEMSA keeps pace with the plans of innovation and automation of its processes. The latest improvement has been another Studer CT730 for inner grinding. This model is specially designed for grinding of medium diameters of very hard materials, like tungsten carbide.

This is the second CT730 and it is a logical consequence of the current plan of machine purchases in order to strengthen the automation of production processes. Machines like this, along with our CAD-CAM system, allow avoiding human interference as much as possible.

Studer CT730 provides several advantages: On one hand it produces homogeneous radius with perfect tangency; moreover, it makes possible a perfect repeatability of those inner shapes for serial production and on the other hand it achieves a great surface finish before polishing.

This second Studer CT730 will help TEMSA enhancing its productivity for the so called easy tooling, allowing us to offer our customers a great variety of tools with a challenging price.

Extrusion dies with split nibs (I). Concentricity

Tungsten carbide dies can have different sizes: from very large to very small. For quite some time, tooling manufacturers have succeeded on developing its technology for cutting the nibs on long enough dies, thus reducing manufacturing costs. Of all tungsten carbide dies, the most demanding for this technology are the extrusion dies, because of the high pressures they are submitted to, which can cause that the upper nib is expelled from the casing.

 

Is it possible to split the upper nibs?

 

TEMSA does it quite frequently and with very good results. The nib is cut at a suitable distance above the extrusion. Many customers ask how we can overcome the concentricity problems between the upper and the lower nib. Any small variation will cause the material to grip and eventually breaking the die. TEMSA solves this problem by smoothing the sharp edges on both tungsten carbide nibs creating a small bevel on both edges. This problem can also be solved by making a small radius. Furthermore, the joint of both nibs can be used for adding air events. With this simple method, we can solve those concentricity problems that could appear on the nibs.

 

Detalle de unión entre núcleos de metal duro para evitar desconcentricidad

Detalle de unión entre núcleos para evitar evitar desvíos de concentricidad

Extrusion dies without a reduction ring

Quite often, the designer of a cold forging process has to bear in mind so many small details that some other really important ones, that could compromise the whole project, can be inadvertently overlooked. We have sometimes noticed this in complex extrusion dies where the designer has forgotten to include a back relief after the extrusion.

If reduction is performed without a reduction ring, then there will be too much friction surface between the material and the die. We must prevent this situation because, due to the pressures and frictions involved, the material will tend to grasp and glue to the internal surface of the extrusion die and this will consequently crack. If the reduction diameter is open few microns, the friction surface will be considerably reduced and the calibrating zone will have a much longer span life. About 2 mm length should be enough.

This we call the reduction ring of an extrusion die.

Extrusion dies without a reduction ring
Design of an extrusion die with the modified by TEMSA