Frequently Asked Questions

Welcome to our FAQ page where we will post as many questions and answers as we can about sheet metal processing.
If you have any questions relating to laser cutting, punching, or any other sheet metal fabrication related issues please click here to email us and we will endevour to come straight back with the answer as well as adding the information to this page.



HTA is based in Rugby just off J1 of the M6. We are therefore well placed to deliver to all parts of the UK mainland



At HTA we regularly make this decision having the ability to both punch and laser cut in house. There are a number of criteria to consider based on the key benefits of each processing route.

CNC Punching is mainly used for materials from 0.5mm - 2.0mm. Whilst materials up to 6mm can be punched this is not normally cost effective or suitable.

CNC punching can be used for components requiring 3 dimensional forms such as louvres, dimples, thread forms etc.

CNC punching is sometimes faster and cheaper than laser cutting thinner material where volumes are higher and there are many holes and features. However where specific tooling is required this will increase the cost.

Laser Cutting requires no tooling and so set up time is minimal. In fact HTA’s latest machine uses single head cutting technology which is almost unique in the industry. This means the cutting head does not have to be changed for different material thicknesses further reducing downtime.

Laser Cutting is the preferred method of processing thicker materials (HTA can laser cut up to 25mm plate), or parts with complex shapes or single line contours. Whilst the machine cost is more expensive, latest technology 6kw machines can rival CNC Punching in some instances for speed.

Laser cutting produces a much higher quality cut edge requiring no additional finishing operations.

Quality Control


In nearly all industry sectors quality control is part of the developing, engineering or manufacturing process in order to ensure that the designed and fabricated products meet the customers' expectations or stay within previously defined tolerances. QC is a part of Total Quality Management (TQM).

Quality starts at the design stage. A TQM (Total Quality Management) system will quantify, by means of precise measurement, the production capability (including measurement capability) of the organisation. This will facilitate improved tolerancing for functionality of the product, the identification of areas of capability associated with specific tolerance (customer) demands. Simply put - measurement is the tool that is used to quantify the capabilities of the people, the processes, the tools, the machines and therefore the organization. The correct application of the above will greatly facilitate right-first-time manufacturing.

To support the production department and the customer as a fully integrated function of the process. Quality and measurement are not add-ons. All processes should include the quality checks for process verification and validation. A major function of Quality control is to control process variation within the defined process capabilities. Most of the data worked with will be captured via measurement systems and processed statistically.

A Coordinate Measuring Machine (CMM) captures 3D data from objects to give the position in XYZ, vectors etc. of the object under investigation. CMMs are used by manufacturing companies to ensure that parts or components are within defined tolerance levels for quality, and to capture statistical process capability data.

HTA are accredited by Lloyds to BSEN ISO 9001:2008 Within this strict quality approval we undertake reqular calibration of all measuring devices to ensure all equipment is compliant to British Standards.



Computer-Aided Design: Software which replaces or augments manual drafting and design. Allows for parts to be designed using computer software, and stored in an electronic database. These CAD files can be converted to a number of different formats for importing into your measurement system software for direct comparison.

CAM refers to computer aided manufacturing or machining. A portable measurement system can be used on the machine for verification or data capture when working with CAM by checking against the model.

A measurement arm is a multi-axis articulated portable measurement system used for a variety of applications including quality control, reverse engineering (modelling), and inspections.

HTA can cut up to 25mm Mild Steel, up to 25mm Stainless Steel and up to 15mm Aluminium.

This is a form of bending, used for sheet metal parts. The machine that bends the metal is called a Press Brake. The lower part of the press contains a V shaped groove. This is called the die. The upper part of the press contains a punch that will press the sheet metal down into the v shaped die, causing it to bend. There are several techniques used here, but the most common modern method is "air bending". Here, the die has a sharper angle than the required bend (typically 85 degrees for a 90 degree bend) and the upper tool is precisely controlled in its stroke to push the metal down the required amount to bend it through 90 degrees. The opening width of the lower die is typically 8 to 10 times the thickness of the metal to be bent (for example, 5mm material could be bent in a 40mm die) the inner radius of the bend formed in the metal is determined not by the radius of the upper tool, but by the lower die width. Typically, the inner radius is equal to 1/6th of the V width used in the forming process.

The press usually has some sort of back gauge to position depth of the bend along the workpiece. The backgauge can be computer controlled to allow the operator to make a series of bends in a component to a high degree of accuracy. Simple machines control only the backstop, more advanced machines control the position and angle of the stop, its height and the position of the two reference pegs used to locate the material. The machine can also record the exact position and pressure required for each bending operation to allow the operator to achieve a perfect angular bend across a variety of operations on the part.

Laser Cutting involves moving a lens assembly carrying a beam of laser light over the surface of the metal. Oxygen or nitrogen or air is fed through the same nozzle from which the laser beam exits. The metal is heated and then burnt by the laser beam, cutting the metal sheet. The quality of the edge can be mirror smooth, and a precision of around 0.1mm can be obtained. Cutting speeds on thin (1.2mm) sheet can be as high as 50m a minute. Most of the laser cutting systems use a CO2 based laser source with a wavelength of around 10um

CNC Punching is performed by moving the sheet of metal between the top and bottom tools of a punch. The top tool (punch) mates with the bottom tool (die), cutting a simple shape (e.g. a square, circle, or hexagon) from the sheet. An area can be cut out by making several hundred small square cuts around the perimeter. A punch is less flexible than a laser for cutting compound shapes, but faster for repetitive shapes (for example, the grille of an air-conditioning unit). A typical CNC punch has a choice of up to 60 tools at any one time that can be rotated to bring any tool to the active punching position.

Rolling is a fabricating process in which the metal is passed through a pair (or pairs) of rolls. There are two types of rolling process, flat and profile rolling. In flat rolling the final shape of the product is either classed as sheet (typically thickness less than 3 mm, also called "strip") or plate (typically thickness more than 3 mm). In profile rolling the final product may be a round bar or other shaped bar, such as a structural section (beam, channel, joist etc). Rolling is also classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is termed as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is termed as cold rolling. Another process also termed as 'hot bending' is induction bending, whereby the section is heated in small sections and dragged into a required radius. Heavy plates tend to be formed using a press process, which is termed forming, rather than rolling.

The sheet metal gauge (sometimes spelled "gage") indicates the standard thickness of sheet metal for a specific material. As the gauge number increases, the material thickness decreases. Sheet metal thickness gauges for steel are based on the weight of steel, allowing more efficient calculation of the cost of material used. The weight of steel is 41.82 pounds per square foot per inch of thickness; this is known as the Manufacturers' Standard Gage for Sheet Steel. For other materials, such as aluminium and brass, the thicknesses will be different.

Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a material with a lower-melting-point between the workpieces to form a bond between them, without melting the workpieces.

Welding is the main focus of steel fabrication. The formed and machined parts will be assembled and tack welded into place then re-checked for accuracy. A fixture may be used to locate parts for welding if multiple weldments have been ordered. The welder then completes welding per the engineering drawings. Steel weldments are occasionally annealed in a low temperature oven to relieve residual stresses.

The three principal machining processes are classified as turning, drilling and milling. Other operations falling into miscellaneous categories include grinding, boring, slotting and sawing. Turning operations are operations that rotate the workpiece as the primary method of moving metal against the cutting tool. Lathes are the principal machine tool used in turning. Milling operations are operations in which the cutting tool rotates to bring cutting edges to bear against the workpiece. Milling machines are the principal machine tool used in milling. Drilling operations are operations in which holes are produced or refined by bringing a rotating cutter with cutting edges at the lower extremity into contact with the workpiece. An unfinished workpiece requiring machining will need to have some material cut away to create a finished product. A finished product would be a workpiece that meets the specifications set out for that workpiece by engineering drawings. For example, a workpiece may be required to have a specific outside diameter. A lathe is a machine tool that can be used to create that diameter by rotating a metal workpiece, so that a cutting tool can cut metal away, creating a smooth, round surface matching the required diameter and surface finish. A drill can be used to remove metal in the shape of a cylindrical hole. Other tools that may be used for various types of metal removal are milling machines, saws, and grinding tools. More recent, advanced machining techniques include laser, or water jet cutting to shape metal workpieces.

Machining requires attention to many details for a workpiece to meet the specifications set out in the engineering drawings. Beside the obvious problems related to correct dimensions, there is the problem of achieving the correct finish or surface smoothness on the workpiece. The inferior finish found on the machined surface of a workpiece may be caused by incorrect clamping, dull tool, or inappropriate presentation of a tool. Frequently, this poor surface finish, known as chatter, is evident by an undulating or irregular finish, and the appearance of waves on the machined surfaces of the workpiece.

Laser Cutting


Yes. At HTA we have experience in laser cutting a range of exotic alloys such as Titanium, Duplex, Alloy 625, Alloy 825 and 904. For any specialist alloys not listed above please feel free to contact us.

Yes. At HTA we have experience in laser cutting a range of high strength steels such as Domex, Weldox, Hardox, S420, S500. For any high strength materials not listed above please feel free to contact us.


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