Notching

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Notching is a metal-cutting process used on sheet-metal or thin bar-stock, sometimes on angle sections or tube. A shearing or punching process is used in a press, so as to cut vertically down and perpendicular to the surface, working from the edge of a work-piece. Sometimes the goal is merely the notch itself, but usually this is a precursor to some other process: such as bending a corner in sheet or joining two tubes at a tee joint, notching one to fit closely to the other.

Contents

Notching is a low-cost process, particularly for its low tooling costs with a small range of standard punches. The capital cost of the punch press can be expensive though, so small fabrication shops often out-source their notching work to a press shop or notching specialist. Notching of large or heavy sections, particularly for large tube fabrication or HVAC, is increasingly carried out by plasma-cutting rather than punch tools. The first punch & die type tool for notching tube & pipe was invented in Chicago by Julius Vogel, who was issued a US patent in 1938. [1]

The accuracy of punch notching is good, depending on the care with which it's carried out. For manual folding work, prior notching can often improve resultant accuracy of the folding itself.

The speed of notching is usually limited by manual handling when loading the workpieces into the press. Pieces some feet long may be manually loaded into a single-stroke press. Smaller pieces are still generally hand-fed, limiting speeds to perhaps 100 strokes / minute.

Almost any workable metal can be notched. It's particularly suitable where the metal is otherwise awkward to drill, such as stainless steels, titanium or previously heat-treated aluminium alloys. It is an operation of removing a small part of metal sheet of desired shape from edge of metal sheet

Tube notching

Bicycle frame in steel tube, notched at the joints before TIG welding or brazing Bicycle Frame Lemond zurich retouched.jpg
Bicycle frame in steel tube, notched at the joints before TIG welding or brazing

Tube notching is commonly performed before joining light-gauge tubes to make a tee or similar joint, as by welding. Either one or both tubes may be notched before assembly. A familiar example of tube notching is in the manufacture of bicycle frames.

End notching works the end of the tube, such as a semicircular concavity to make the base of a tee, or a convex vee to fit into a mitre.

Vee-notched tube, bent for assembly of a mitred joint Notched tube.png
Vee-notched tube, bent for assembly of a mitred joint

Side notching (also called offset notching) works the side of a tube with a vee notch for bending, semicircular or vee notches for tee joint.

Tube being hollow, it's not practical to use a simple punch operation to notch it, as it would be squashed. Although punching is possible, it requires support mandrels and awkward handling. Where tube is worked with a punch press other than for side notching, this is generally described as slotting.

Tube notching for fabrication of circular tube is thus most commonly done with a rotary hole saw in which a hole saw of the diameter of the tube being attached to is fed into the stock to be notched at a semi-perpendicular angle. This produces a semi-circular notch. Rather than using large presses, such saw notching may only require a simple jig, also making it suitable for on-site working. [2] [3]

A much more accurate way of notching the end of tube stock is to use a specially made milling cutter called an end mill. The stock to be notched is clamped into a vise and can then be fed slowly and accurately into a rotating, hardened metal, end mill. The equipment required for this method is considerably more expensive than the hole saw method and does not lend well to the same portability of the hole saw method as the machine is usually bolted to the floor for stability and safety reasons. This method of end notching is much faster and thus greatly minimizes the chance of damaging the stock either by warping due to heat build up or by squashing as can still happen with a hole saw. [4]

Notching in thin-wall tube may also be carried out by abrasive tools, reducing some of the risk of damage from a hole saw snatching. This also allows more complex shapes to be performed, such as vee notches. [3] In some cases, a helical end mill cutter may be used. [3]

Computer numerical control (CNC) notching is enabling designers to work with more complex geometries.

Notch and bend

Vee notches in tube, particularly square tube, may be cut so deep as to cut almost through the tube: three sides of a square tube. This then allows torner[ check spelling ], usually finished by welding.

On a smaller scale for jewellery making, this operation is performed by hand-filing precious-metal strip before bending and soldering to make box frames or stone mounts.

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A die is a specialized machine tool used in manufacturing industries to cut and/or form material to a desired shape or profile. Stamping dies are used with a press, as opposed to drawing dies and casting dies which are not. Like molds, dies are generally customized to the item they are used to create.

Numerical control Computer control of machine tools, lathes and milling machines, also used on 3D printers

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Drilling Cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials

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Metal fabrication

Metal fabrication is the creation of metal structures by cutting, bending and assembling processes. It is a value-added process involving the creation of machines, parts, and structures from various raw materials.

Grinding machine

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Sheet metal

Sheet metal is metal formed by an industrial process into thin, flat pieces. Sheet metal is one of the fundamental forms used in metalworking, and it can be cut and bent into a variety of shapes. Countless everyday objects are fabricated from sheet metal. Thicknesses can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate steel or "structural steel".

Hydroforming Method of shaping metal through pressurized water

Hydroforming is a cost-effective way of shaping ductile metals such as aluminium, brass, low alloy steel, and stainless steel into lightweight, structurally stiff and strong pieces. One of the largest applications of hydroforming is the automotive industry, which makes use of the complex shapes made possible by hydroforming to produce stronger, lighter, and more rigid unibody structures for vehicles. This technique is particularly popular with the high-end sports car industry and is also frequently employed in the shaping of aluminium tubes for bicycle frames.

Punching

Punching is a forming process that uses a punch press to force a tool, called a punch, through the workpiece to create a hole via shearing. Punching is applicable to a wide variety of materials that come in sheet form, including sheet metal, paper, vulcanized fibre and some forms of plastic sheet. The punch often passes through the work into a die. A scrap slug from the hole is deposited into the die in the process. Depending on the material being punched this slug may be recycled and reused or discarded.

Tool and die maker

Tool and die makers are a class of machinists in the manufacturing industries. Variations on the name include tool maker,toolmaker, die maker,diemaker, mold maker,moldmaker or tool jig and die-maker, or fitter, depending on which area of concentration or industry an individual works in.

Bending (metalworking)

Bending is a manufacturing process that produces a V-shape, U-shape, or channel shape along a straight axis in ductile materials, most commonly sheet metal. Commonly used equipment include box and pan brakes, brake presses, and other specialized machine presses. Typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork.

Piping and plumbing fitting

A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.

JD Squared

JD Squared, Inc. is an American manufacturer of tube and pipe benders. Founded in 1982 and based in Johnson City, Tennessee, the company has manufactured fabrication tools since 1982, starting with tube and pipe benders and later expanding to other fabrication tools. JD Squared is a privately owned Florida corporation. Robert Hughes is the owner and Chief Engineer.

Press brake

A press brake is a machine pressing tool for bending sheet and plate material, most commonly sheet metal. It forms predetermined bends by clamping the workpiece between a matching punch and die.

Perforated metal, also known as perforated sheet, perforated plate, or perforated screen, is sheet metal that has been manually or mechanically stamped or punched using CNC technology or in some cases laser cutting to create different holes sizes, shapes and patterns. Materials used to manufacture perforated metal sheets include stainless steel, cold rolled steel, galvanized steel, brass, aluminum, tinplate, copper, Monel, Inconel, titanium, plastic, and more.

Bar stock

Bar stock, also (colloquially) known as blank, slug or billet, is a common form of raw purified metal, used by industry to manufacture metal parts and products. Bar stock is available in a variety of extrusion shapes and lengths. The most common shapes are round, rectangular, square and hexagonal or hex. A bar is characterised by an "enclosed invariant convex cross-section", meaning that pipes, angle stock and objects with varying diameter are not considered bar stock.

Tube bending

Tube bending is any metal forming processes used to permanently form pipes or tubing. Tube bending may be form-bound or use freeform-bending procedures, and it may use heat supported or cold forming procedures.

Roll forming Continuous bending of a long strip of sheet metal into a desired cross-section

Roll forming, also spelled roll-forming or rollforming, is a type of rolling involving the continuous bending of a long strip of sheet metal into a desired cross-section. The strip passes through sets of rolls mounted on consecutive stands, each set performing only an incremental part of the bend, until the desired cross-section (profile) is obtained. Roll forming is ideal for producing constant-profile parts with long lengths and in large quantities.

Disc cutter

A disc cutter is a specialised, often hand-held, power tool used for cutting hard materials, ceramic tile, metal, concrete, and stone for example. This tool is very similar to an angle grinder, chop saw, or even a die grinder, with the main difference being the cutting disc itself. This tool is highly efficient at cutting very hard materials, especially when compared to hand tools.

Turret punch


A turret punch or turret press is a type of punch press used for metal forming by punching.

References

  1. "About Vogel Tool and Die - Addison, Illinois". www.vogeltool.com. Retrieved 2018-10-04.
  2. "Notch Master tube notching jig". Medford Tools.
  3. 1 2 3 Rusch, C. & Holmes, E. (2003). "Notching tube and pipe: Examining three common methods" (PDF). TPJ - the Tube & Pipe Journal.
  4. "Mittler Brothers Machine and Tool Ultimate Tube Notcher". Mittler Brothers Machine and Tool.