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Only the highest-quality raw materials are used in the manufacture of our consumables. Design and construction are application-specific and based on close cooperation with end-users. We use customer feedback for continually fine-tuning and expanding our product offering.
The wedge angle essentially determines how sharp the knife is. In theory, a very narrow wedge angle makes for a very sharp knife that exerts a minimal drag force on the material being cut. At the same time, a small wedge angle also means that the cutting process puts a great deal of stress on a very thin cutting edge, which may affect stability. The narrower the wedge angle, the greater the instability. For this reason, the appropriate wedge angle is always a compromise between blade sharpness and stability. The geometry of any Zünd blade is carefully calculated to deliver the best possible cutting results for different types of materials. Our blade specifications include a selection of suitable materials for each blade type.
Another factor that significantly affects the cutting force of a blade is the cutting angle. With drag kinves, a small cutting angle reduces the drag force on the material; on the other hand, a small cutting angle also results in larger overcuts.
|Drag knives||Oscillating knife – flat||Oscillating knife – pointed|
For each blade, a maximum cutting depth is specificied that corresponds to the length of the cutting edge. Naturally, the maximum thickness of material that can be processed with any particular blade also depends on the type of material being cut. Please note that the set base depth (the distance by which the material is through-cut) needs to be added to the material thickness when calculating maximum cutting depth.
t – Material thickness
z – Base depth
TM – Cutting depth = material thickness t + base depth z
The pre-cut x1 refers to the distance between the center of the blade (its axis of rotation) and the point of entry of the cutting edge into the material in the direction of travel. The post-cut x2 is the distance between the axis of rotation and the last point of contact between the edge of the blade and the material.
When oscillating, cutting occurs as the blade moves up and down while travelling through the material. With flat oscillating blades, the wide tip of the blade creates considerable overcuts; pointed oscillating blades are therefore better suited for cutting small radii and detailed contours.
Overcuts will cause distortions in contours. If necessary, there are steps that can be taken to minimize this effect. Overcuts can be minimized or eliminated by changing the direction of cut lines in the file, cutting from the back of the material, and by using blades that produce the smallest possible overcuts. Overcut information is provided in the technical data provided for each type of blade.
|Drag blades||Oscillatiing blade, flat||Oscillatiing blade, pinted|
Blade geometry as well as cutting depth factor into the overcut. In this chapter, we will explain how to calculate overcuts for any blade and material thickness. The blades chosen in the examples below are the pointed oscillating blade Z20 and the drag knife Z11.
The cutting depth TM is based on the material thickness t and the base depth z. Take the values specified in the product description for each knife and enter them into the formula given below. The result will be the applicable pre- and post-cuts in mm.
|Example: Z20||Example: Z11|
|TM||Cutting depth = material thickness t + base depth z|
|Formula||x = 1.2 + 0.11 x TM|
|Cutting depth||TM = 10.2 mm|
|Pre-cut||x1 = 2.322 mm|
|Formula||x1,2 = 0.58 x TM|
|Cutting depth||TM = 5.2 mm|
|Pre-cut||x1 = 3.016 mm|
|Post-cut||x2 = 3.016 mm|