How to choose a Guillotine | Webster Machinery Guide
What is the thickest material you will cut and what is its tensile strength?
The maximum thickness capacity quoted for a guillotine is generally based around mild steel at a tensile strength of between 40 and 45kg/mm2. It also assumes that the machine is in perfect working order, with all setting made correctly (rake angle, blade gap & sharp blade edges).
When cutting at maximum thickness, it should be remembered that low quality material can often exceed the specified tensile strength figure. Therefore, if the machine will be required to regularly cut to capacity, it is recommended you consider selecting the next model up (i.e. an 8mm machine for 6mm cutting)
To calculate the machine cutting capacity for other material types, use the following equation
Using the following material hardness’s, a standard 6mm machine will cut 8mm aluminium and 4.8mm stainless steel.
Aluminium at 25kg/mm2 hardness = 45 x 36 / 25 = 8mm. Stainless steel at 70kg/mm2 hardness = 45 x 36 / 70 = 4.8mm.
(Although cutting of mesh and checker plate is possible, the uneven nature of the surface and hardness of the raised sections will result in poor cutting results when cutting normal sheet material)
A hydraulic machine will cut to its capacity regardless of the length of cut. Due to its momentum, a mechanical machine may cut over capacity when cutting short lengths. This is however not recommended as stalling a cut can chip the blades.
Length Capacity
What is the maximum length of material you will cut. Will you cut across the diagonals?
Will you want to have one section of blade for rough cutting (i.e. buy a 3m machine, giving 2.5m of good blade and 0.5m of blade for miscellaneous cutting)
There are two designs of hydraulic machine. The first has top mounted rams that push the top blade down. The other design has its rams mounted below the blade and pull down. The advantage of the push design is that it is a more compact machine and often has gaps in the side frames to allow cutting longer material lengths than the machine capacity. (For example the YSD HGN guillotine)
Machine Design
- Recommended design - Parallel guided
The top blade runs in vertical guides up and down during the cutting cycle. This gives an accurate cut with the minimum of component distortion. The blades are normally interchangeable top and bottom and have four cutting edges. It is generally possible to adjust the gap between the blades and alter the rake angle. This is important where a quality cut is required on thinner gauge material. (Manufacturer of Parallel guided machines – Safan, Schroder & YSD). - Swing beam
The top blade is fitted to a large heavy fabricated triangular section that is pivoted at the back of the machine side frames. As the downward motion follows an arc, the top blade has a twist to maintain the required cutting angle. This distortion results in no interchangeable top and bottom blades, two cutting edges and a significant twist to the blank. Adjustment of the blade gap is sometimes possible but the rake angle is fixed.
Guarding
All new machines we sell are sold with the CE mark and appropriate guarding. This generally means a fixed front finger guard, high side fences and a rear open back protected by light guards. Alternatives options are available but if full guarding is required it is recommended to only consider a used machine built after 1995 or a new model.