Intro

Bridge Metal Industries offers a comprehensive range of services and manufacturing processes to support the Point of Purchase industry. They can be broken into three primary groups: 1. Custom lighting and light boxes, 2. Display components and hardware and 3. Complete finished displays. We provide design ideas or work from customer supplied prints to build a prototype for future large and small run production. In addition, we have a Powder coating line for finishing, pack out/assembly areas, and are capable of storing and drop shipping individual displays. We currently have the largest and most diversified metal manufacturing facility in the country in an 85,000 sq. ft. facility. We are dedicated to servicing the Point of Purchase industry.

Prototyping

is the process of quickly putting together a working model prototype in order to test various aspects of a design,illustrate ideas or features and gather early user feedback. Prototyping is often treated as an integral part of the system design process, where it is believed to reduce project risk and cost. Often one or more prototypes are made in a process of incremental development where each prototype is influenced by the performance of previous designs, in this way problems or deficiencies in design can be corrected. When the prototype is sufficiently refined and meets the functionality, robustness, manufacturability and other design goals, the product is ready for production.

ADVANTAGES OF PROTOTYPING
+ Prototype gives users an idea of what the final system looks like
+ Encourages active participation among users and producer
+ Enables a higher output for user
+ Cost effective (Development costs reduced)
+ Increases system development speed
+ Assists to identify any problems with the efficacy of earlier design, requirements analysis and coding activities
+ Helps to refine the potential risks associated with the delivery of the system being developed

DISADVANTAGES OF PROTOTYPING
- User’s expectation on prototype may be above its performance
- Producer might produce a system inadequate for overall organization needs
- Producer might get too attached to it (might cause legal involvement)
- Often lack flexibility
- Not suitable for large applications

Computer-aided design

CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.

CAD has become an especially important technology, with benefits, such as lower product development costs and a greatly shortened design cycle, because CAD enables designers to lay out and develop their work on screen, print it out and save it for future editing, saving a lot of time on their drawings.

CNC

The abbreviation CNC stands for computer numerical control, and refers specifically to a computer "controller" that reads G-code instructions and drives the machine tool , a powered mechanical device typically used to fabricate metal components by the selective removal of metal. CNC does numerically directed interpolation of a cutting tool in the work envelope of a machine. The operating parameters of the CNC can be altered via software load program. The introduction of CNC machines radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action have been dramatically reduced. With the increased automation of manufacturing processes with CNC machining , considerable improvements in consistency and quality have been achieved. CNC automation reduced the frequency of errors and provided CNC operators with time to perform additional tasks. CNC automation also allows for more flexibility in the way parts are held in the manufacturing process and the time required to change the machine to produce different components.In a production environment, a series of CNC machines may be combined into one station, commonly called a "cell", to progressively machine a part requiring several operations.

Metal Fabrication

Fabrication, when used as an industrial term, applies to the building of machines and structures by cutting, shaping and assembling components made from raw materials. Small businesses that specialize in metal are called fab shops.

Steel fabrication shops and machine shops have overlapping capabilities, but fabrication shops generally concentrate on the metal preparation, welding and assembly aspect while the machine shop is more concerned with the machining of parts.

Metal fabrication is a value added process that involves the construction of machines and structures from various raw materials. A fab shop will bid on a job, usually based on the engineering drawings , and if awarded the contract will build the product.

RAW MATERIALS
Plate Metal formed and Expanded Metal
Tube stock
Structural steel
Sectional Metals (I beams, W beams, C-channel...)
Welding Wire

HARDWARE

CASTINGS

FITTINGS

FORMING

Hydraulic brake with v-dies are the most common method of forming metal. The cut plate is placed in the press and a v-shaped die is pressed a predetermined distance to bend the plate to the desired angle.
Tube bending machines have specially shaped dies and mandrels to bend tubular sections without kinking them.
Rolling machines are used to form plate steel into a round section.

Machining

Fab shops will generally have a limited machining capability including; metal lathes, mills, magnetic based drills along with other portable metal working tools.

Welding

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, if welding is detailed, or per his own judgment if no welding details are provided.

Final assembly and finishing

After the weldment has cooled it is generally sand blasted, primed and painted. Any additional manufacturing specified by the customer is then completed. The finished product is then inspected and shipped.

Punch press

Punch press is a type of machine press used for forming and cutting material. The punch press can be small and manually operated and hold one simple Die set, or be very large, CNC operated, and hold a much larger and complex die set.
A Die set consists of a set of male punches and female dies which, when pressed together, may form a hole in a workpiece or may deform the workpiece in some desired manner. The punches and dies are removable with the punch being temporarily attached to the end of a ram during the punching process. The ram moves up and down in a vertically linear motion.

Today's machines are commonly CNCcontrolled and are mostly powered with an hydraulic ram to enable the punching process. Commonly machines are large metal framed equipment. All punch press machines have a table or bed with brushes or rollers mounted in the tables to allow the sheet metal workpiece to traverse with low friction. Brushes are commonly used in production environments where minimal scratching to the workpiece is required, such as brushed aluminium or high polished materials. The main bed of most machines is called the 'Y' Axis with the 'X' Axis being at right angles to that and allowed to traverse under CNC control. Dependent on the size of the machine, the beds and the sheet metal workpiece weight, then the motors required to move these axis tables can vary in size and power.

As a metal forming process, the punch press is used for the highest volume production. Cycle times are often measured in sheet yield as a percentage of waste to parts required ratios per sheet processed. As most programming is done by skilled CAD/CAM operators parts within the sheet workpiece are commonly nested.Machine setters are mostly used to set up tooling and programming but thereafter once the machine is running an operator of low skill can oversee its continued operation. Often one operator will monitor several punch presses simultaneously making this one of the lowest cost metal manufacturing processes.

Punch presses are usually referred to by their tonnage. In a production environment a 20 ton press is mostly the prevalent machine used today. The tonnage needed to cut and form the material is well known so sizing tooling for a specific job is a fairly straightforward task.

Laser cutting

Laser cutting is a technology that uses a laser to cut materials, and is usually used in industrial manufacturing. Laser cutting works by directing the output high power laser, by computer, at the material to be cut. The material then either melts, burns or vaporizes away leaving an edge with a high quality surface finish. Industrial laser cutters are used to cut flat-sheet material as well as structural and piping materials.

COMPARISON TO MECHANICAL CUTTING
Advantages of laser cutting over mechanical cutting vary according to the situation, but two important factors are the lack of physical contact (since there is no cutting edge which can become contaminated by the material or contaminate the material), and to some extent precision (since there is no wear on the laser). There is also a reduced chance of warping the material that is being cut as laser systems have a small heat affected zone. Some materials are also very difficult or impossible to cut by more traditional means. One of the disadvantages of laser cutting may include the high energy required.

PROCESS
Laser cutters usually work much like a milling machine would for working a sheet in that the laser (equivalent to the mill) enters through the side of the sheet and cuts it through the axis of the beam. In order to be able to start cutting from somewhere else than the edge, a pierce is done before every cut. Piercing usually involves a high power pulsed laser beam which slowly (taking around 5-15 seconds for half-inch thick stainless steel, for example makes a hole in the material.

Machine press

PRESS
A press, or a machine press is a tool used to work metal (typically steel) by changing its shape and internal structure.
A forge press reforms the workpiece into a three dimensional object — not only changing its visible shape but also the internal structure of the material. A stronger part results from this process than if the object was machined.

BENDING
Bending is a typical operation performed and occurs by a machine pressing, or applying direct pressure, to the material and forcing it to change shape.A press brake is a typical machine for this operation.
An easy to understand type of machine press is a set of rollers. Metal is fed into the rollers, which are turning to pull the material through. The space between the rollers is smaller than the unfinished metal, and thus the metal is made thinner and/or wider.

COINING, EMBOSSING & FORMING
Another kind of press is a set of plates with a relief, or depth-based design, in them. The metal is placed between the plates, and the plates are pressed up against each other, deforming the metal in the desired fashion. This may be coining or embossing or forming.

PUNCH PRESS
A punch press is used for forming holes.

BRAKE PRESS
A brake press is a special type of machine press that bends sheetmetal into shape.
A good example of the type of work a brake press can do is the backplate of a computer case. Other examples include brackets, frame pieces and electronic enclosures just to name a few. Some press brakes have CNC controls and can form parts with accuracy to a fraction of a millimeter. These machines can be dangerous considering the knife-edge bending dies and powerful 100+ ton bending force. However in the hands of a skilled operator the machine presents minimum hazard.

Machine presses are used extensively around the world for shaping all kinds of metals to a desired shape. A typical toaster (for bread) has a metal case that has been bent and pressed into shape by a machine press.

Machine presses have a high hazardous level, so safety measures must always be taken. Injuries in a press may be permanent, since there are over 100s tons on top of a limb. Bimanual controls (both hands need to be on the buttons to make the press work) are a very good way to prevent accidents. Also light sensors that keep the machine from working if the operator is in range of the die (tool that goes inside the press to shape metal), or any limbs is in range.

Rolling (metalworking)

Rolling is a fabricating process in which the metal, plastic, paper, glass , etc. is passed through a pair 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 rod 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 metal is below its recrystallization temperature the process is termed as cold rolling.

Progressive Stamping Die

A progressive stamping die ("die") is a metalworking device that is designed and built to convert a strip of metal raw material into parts that conform to blueprint specifications. The "dies" are placed into a stamping press. As the stamping press moves up, the die opens. As the stamping press moves down, the die closes. The raw material (metal) moves through the die while the die is open, being fed into the die a precise amount with each stroke of the press. When the die closes, the die performs its work on the metal and one or more finished parts are ejected (usually by gravity) from the die.

The stamping die can modify the raw material in several ways, such as bending, coining, and punching. Holes that are cut into the raw material can be almost any shape. Since additional work is done in each "station" of the die, it is important that the strip be advanced very precisely so that it aligns within a few thousandths of an inch as it moves from station to station. Bullet shaped or conical "pilots" enter previously pierced round holes in the strip to assure this alignment since the feeding mechanism usually cannot provide the necessary precision in feed length.
The key components of dies are made of tool steel to withstand the high shock loading involved, retain the necessary sharp cutting edge, and resist the abrasive forces involved. An excellent example of the product of a progressive die is the lid of a beer or soft drink can. The pull tab is made in one progressive die and then automatically mated to the lid which is made in another progressive die.

Gas metal arc welding(MIG)

Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems , as well as alternating current, can be used. There are four primary methods of metal transfer in GMAW, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.

EQUIPMENT
To perform gas metal arc welding, the basic necessary equipment is a welding gun, a wire feed unit, a welding power supply, an electrode wire, and a shielding gas supply.

WELDING GUN AND WIRE UNIT

Below: GMAW torch nozzle cutaway image.
(1) Torch handle
(2) Molded phenolic dielectric (shown in white) and threaded metal nut insert (yellow) (3) Shielding gas nozzle
(4) Contact tip
(5) Nozzle output face

SHIELDING GAS
Shielding gases are necessary for gas metal arc welding to protect the welding area from atmospheric gases such as nitrogen and oxygen, which can cause fusion defects, porosity, and weld metal embrittlement if they come in contact with the electrode, the arc, or the welding metal. This problem is common to all arc welding processes, but instead of a shielding gas, many arc welding methods utilize a flux material which disintegrates into a protective gas when heated to welding temperatures.

Gas tungsten arc welding(TIG)

Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas(usually an inert gas such as argon, and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. A constant-current welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.

GTAW is most commonly used to weld thin sections of stainless steel and light metals such as aluminum, magnesium , and copper alloys. The process grants the operator greater control over the weld than competing procedures such as shielded metal arc welding and gas metal arc welding, allowing for stronger, higher quality welds.

However, GTAW is comparatively more complex and difficult to master, and furthermore, it is significantly slower than most other welding techniques. A related process, plasma arc welding, uses a slightly different welding torch to create a more focused welding arc and as a result is often automated.

OPERATION
Manual gas tungsten arc welding is often considered the most difficult of all the welding processes commonly used in industry. Because the welder must maintain a short arc length, great care and skill are required to prevent contact between the electrode and the workpiece. Unlike other welding processes, GTAW normally requires two hands, since most applications require that the welder manually feed a filler metal into the weld area with one hand while manipulating the welding torch in the other. However, some welds combining thin materials (known as autogenous or fusion welds) can be accomplished without filler metal; most notably edge, corner and butt joints.
To strike the welding arc, a high frequency generator provides a path for the welding current through the shielding gas, allowing the arc to be struck when the separation between the electrode and the workpiece is approximately 1.5–3 mm (0.06–0.12 in). Bringing the two into contact also serves to strike an arc, but this can cause contamination of the weld and electrode. Once the arc is struck, the welder moves the torch in a small circle to create a welding pool, the size of which depends on the size of the electrode andthe current. While maintaining a constant separation between the electrode and the workpiece, the operator then moves the torch back slightly and tilts it backward about 10–15 degrees from vertical. Filler metal is added manually to the front end of the weld pool as it is needed.
Welders often develop a technique of rapidly alternating between moving the torch forward (to advance the weld pool) and adding filler metal. The filler rod is withdrawn from the weld pool each time the electrode advances, but it is never removed from the gas shield to prevent oxidation of its surface and contamination of the weld. Filler rods composed of metals with low melting temperature, such as aluminum, require that the operator maintain some distance from the arc while staying inside the gas shield. If held too close to the arc, the filler rod can melt before it makes contact with the weld puddle. As the weld nears completion, the arc current is often gradually reduced to prevent the formation of a crater at the end of the weld.

EQUIPMENT: GTAW torch with various electrodes, cups, collets and gas diffusers

Spot welding

Spot welding is a type of resistance welding used to weld various sheet metals. Typically the sheets are in the 0.5-3.0 mm thickness range. The process uses two shaped copper alloy electrodes to concentrate welding current and force between the materials to be welded. The result is a small "spot" that is quickly heated to the melting point, this forms a nugget of welded metal after the current is removed. The amount of heat released in the spot is determined by the amplitude and duration of the current. The current and duration are chosen to match the material, the sheet thickness and type of electrodes. Applying the current for too long can result in molten metal being expelled as weld splash, or can even burn a hole right through the materials being welded.

APPLICATIONS
Spot welding is typically used when welding particular types of metal steel sheet metal. Thicker stock is difficult to heat up from a single spot, as the heat can flow into the surrounding metal too easily. Spot welding can be easily identified on many sheet metal goods, such as metal pails (buckets). Aluminum alloys can also be spot welded. However, their much higher thermal conductivity and electrical conductivity mean that up to three times higher welding currents are needed. This requires larger, more powerful, and more expensive welding transformers.
Due to changes in the resistance of the metal as it starts to liquefy, the welding process can be monitored in real-time to ensure a perfect weld every time, using the most recent advances in monitoring/feedback control equipment. The resistance is measured indirectly, by measuring the voltage at and current through the electrodes.

Extrusion

Extrusion is a manufacturing process used to create long objects of a fixed cross-sectional profile. A material, often in the form of a billet, is pushed and/or drawn through a die of the desired profile shape. Hollow sections are usually extruded by placing a pin or piercing mandrel inside of the die, and in some cases positive pressure is applied to the internal cavities through the pin. Extrusion may be continuous (producing indefinitely long material) or semi-continuous (producing many short pieces). Some materials are hot drawn whilst others may be cold drawn.

The feedstock may be forced through the die by various methods. A single or twin screw auger, powered by an electric motor, or a ram, driven by hydraulic pressure (for steel alloys and titanium alloys for example), oil pressure (for aluminum), or in other specialized processes such as rollers inside a perforated drum for the production of many simultaneous streams of material. Extrusion simulation tools help to understand the extrusion process and to optimize development of tools and products. Commonly extruded materials include metals, polymers, ceramics, and foodstuffs. Metal extrusion is used by industry for various purposes such as:
- Copper pipe for plumbing.
- Aluminium extrusion profiles for tracks, frames, rails, and mullions.
- Steel rods or track.
- Titanium aircraft components including seat tracks, engine rings, and other structural parts

Powder coating

Powder coating is a type of dry coating, which is applied as a free-flowing, dry powder. The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. The coating is typically applied electrostatically and is then cured under heat to allow it to flow and form a "skin." The powder may be a thermoplastic or a thermoset polymer. It is usually used to create a hard finish that is tougher than conventional paint. Powder coating is mainly used for coating of metals, such as "white goods", aluminium extrusions, and automobile and motorcycle parts. Newer technologies allow other materials, such as MDF medium-density fibreboard, to be powder coated using different methods.

ADVANTAGES & DISADVANTAGES OF POWDER COATING
There are several advantages of powder coating over conventional liquid coatings:
+ Powder coatings emit zero or near zero volatile organic compounds (VOC).
+ Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging.
+ Powder coating overspray can be recycled and thus it is possible to achieve nearly 100% utilization of the coating.
+ Powder coating production lines produce less hazardous waste than conventional liquid coatings.
+ Capital equipment and operating costs for a powder line are generally less than for conventional liquid lines.
+ Powder coated items generally have fewer appearance differences between horizontally coated surfaces and vertically coated surfaces than liquid coated items.
+ A wide range of specialty effects is easily accomplished which would be impossible to achieve with other coating processes.

- While powder coatings have many advantages over other coating processes, there are limitations to the technology.
- While it is relatively easy to apply thick coatings which have smooth, texture free surfaces, it is not as easy to apply smooth thin films. As the film thickness is reduced, the film becomes more and more orange peeled in texture due to the particle size and TG (glass transition temperature)of the powder.

+/- Powder coatings have a major advantage in that the overspray can be recycled. However, if multiple colors are being sprayed in a single spray booth, this may limit the ability to recycle the overspray.

THE POWDER COATING PROCESS
The powder coating process involves three basic steps:
Part preparation or the Pre treatment
The powder application
Curing
Part Preparation Processes & Equipment
Removal of oil, soil, lubrication greases, metal oxides, welding scales etc. is essential prior to the powder coating process. It can be done by a variety of chemical and mechanical methods. The selection of the method depends on the size and the material of the part to be powder coated, the type of soil to be removed and the performance requirement of the finished product.

POWDER APPLICATION PROCESSES
The most common way of applying the powder coating to metal objects is to spray the powder using an electrostatic gun, or Corona gun. The gun imparts a negative electric charge on the powder, which is then sprayed towards the object, which is grounded. The object is then heated, and the powder melts into a uniform film, and is then cooled to form a hard coating. It is also common to heat the metal first and spray the powder onto the hot substrate. Preheating can help to achieve a more uniform finish but can also create other problems, such as runs caused by excess powder. See the article "Fusion Bonded Epoxy Coatings".
Another type of gun is called a Tribo gun, which charges the powder by (triboelectric) friction. In this case, the powder picks up a positive charge while rubbing along the wall of a Teflon tube inside the barrel of the gun. These charged powder particles then adhere to the grounded substrate. Using a Tribo gun requires a different formulation of powder than the more common Corona guns. Tribo guns are not subject to some of the problems associated with Corona guns, however, such as back ionization and the Faraday Cage Effect.

CURING
When a thermoset powder is exposed to elevated temperature, it begins to melt, flows out, and then chemically reacts to form a higher molecular weight polymer in a network-like structure. This cure process, called crosslinking, requires a certain degree of temperature for a certain length of time in order to reach full cure and establish the full film properties that the material was designed for. Normally the powders cure at 200 °C in 10 mins. The curing schedule could vary according to the manufacturer's specifications
The application of energy to the product to be cured can be accomplished by convection cure ovens or infrared cure

Chrome plating

Chrome plating is a finishing treatment utilizing the electroplating, electrolytic deposition of chromium. The most common form of chrome plating is the thin, decorative bright chrome, which is typically a 10 micrometre µm layer over an underlying polished nickel plate. It imparts a highly reflective finish to items such as metal furniture frames and automotive trim. Thicker deposits, up to 1000 µm, are called hard chrome and are used in industrial equipment to reduce friction and wear and to restore the dimensions of equipment that has experienced wear. Black chrome is a variant in which process conditions are altered to give the plating a dark color.

TYPICAL PLATING PROCESS
The component will generally go through these different stages:
1) Degreasing to remove heavy soiling.
2) Manual cleaning to remove all residual traces of dirt and surface impurities.
3) Component placed on a jig or rack.
4) Various pretreatments depending on the substrate.
5) Placed into the chrome plating vat and allowed to warm to solution temperature.
6) Plating current applied and component is left for the required time to attain thickness.

There are many variations to this process depending on the type of substrate being plated upon. Different etching solutions are used for different substrates, Hydrochloric, Hydroflouric, Sulphuric acids can be used, ferric chloride is also popular for the etching of Nimonic alloys. Sometimes the component will enter the chrome plating vat electrically live. Sometimes the component will have a conforming anode either made from lead/tin or platinized titanium. A typical hard chrome vat will plate at about 25 micrometres (0.001 inches) per hour. To put that into perspective a human hair is between 50 to 100 micrometres.

Anodizing

Anodizing, or anodising, is an electrolytic passivation process used to increase the thickness and density of the natural oxide layer on the surface of metal parts. This process is of no use on carbon steel because rust puffs up and flakes off, constantly exposing new metal to corrosion. But on many other metals, anodizing increases corrosion resistance and wear resistance, and provides better adhesion for paint primers and glues than bare metal. Anodic films can also be used for a number of cosmetic effects, either with thick porous coatings that can absorb dyes or with thin transparent coatings that add interference effects to reflected light. Anodization changes the microscopic texture of the surface and can change the crystal structure of the metal near the surface. Coatings are often porous, thick ones inevitably so, so a sealing process is often used to improve corrosion resistance. The process derives its name from the fact that the part to be treated forms the anode portion of an electrical circuit in this electrolytic process. Anodizing can prevent galling of threaded components. Anodic films are generally much stronger and more adherent than most paints and platings, making them less likely to crack and peel. Anodic films are most commonly applied to protect aluminium alloys, although processes also exist for titanium,zinc, magnesium, and niobium.

ANODIZED ALUMINUM
Aluminum is anodized both to increase corrosion resistance and to allow dyeing. When exposed to the atmosphere, aluminum forms a passive oxide layer which provides moderate protection against corrosion. In its pure form aluminum self-passivates very effectively, but its alloys, especially 6000 series due to the magnesium content, are far more prone to atmospheric corrosion and therefore benefit from the protective quality of anodising. Aluminum alloy parts are therefore anodized to increase the thickness of this layer for corrosion resistance. Most aluminum aircraft parts including major components are anodized. Anodized aluminum can be found in many consumer products like mp3 players, flashlights, cookware, cameras, sporting goods, and many other products both for corrosion resistance and the ability to be dyed. The most widely used anodizing specification, MIL-A-8625, defines three types of aluminum anodization. Type I is Chromic Acid Anodization, Type II is Sulphuric Acid Anodization and Type III is sulphuric acid hardcoat anodization. AMS 2469 is very similar to Type III.

Where appearance is important, the oxide surface can be dyed before the sealing stage, as the dye enters the pores in the oxide surface. The number of dye colors is almost endless; however, the colors produced tend to vary according to the base alloy. Though some may prefer lighter colors, in practice they may be difficult to produce on certain alloys such as high-silicon casting grades and 2000-series (with its high copper content). Another concern is the lightfastness of organic dyestuffs—some colours (reds and blues) are particularly prone to fading. Black dyes and gold produced by inorganic means ("Ferric ammonium oxalate" ferric ammonium oxalate) are more lightfast.

Alternatively, metal (usually tin) can be electrolytically deposited in the pores of the anodic coating to provide colors that are more lightfast. Metal dye colors range from pale champagne to black.bronze shades are preferred for architectural use.

Alternatively the color may be produced integral to the film. This is done during the anodizing process using organic acids mixed with thesulfuric electrolyte and a pulsed current.

After dyeing, the surface is usually sealed by using hot water or steam, sometimes mixed with nickel acetate or other anti-bloom agents, to convert the oxide into its HYPERLINK "http://en.wikipedia.org/wiki/Hydrated" \o "Hydrated" hydrated form. This reduces the porosity of the surface as the oxide swells. This also reduces or eliminates dye bleed out and can increase corrosion resistance. Sealing at 20 °C in nickel-cobalt salts, cold sealing, when the pores are closed by impregnation is also popular due to energy savings. Coatings sealed in this method are not suitable for adhesive bonding

LIGHTING TERMINOLOGY

Accent Lighting - concentrated light on a subject which highlights it and caused it to stand out from its surrounding. Depending on degree of drama desired, accent light should minimally be 10x the general light or ambient light.

Green Lamp Technology - this technology uses capsule dosing to precisely control the amount of mercury in each lamp. Long-life lamps such as the Philips ALTO further reduce the need to replace lamps and, as a result, decrease the amount of mercury used over life of any lighting installation.

Candela (cd) (Luminous Intensity) - the intensity base unit for light. Intensity is the luminous flux emitted from a point per solid angle into a particular direction, regardless of distance.

Candlepower (cp) - luminous intensity expressed in candelas.

Color Rendering Index (CRI) - a method for describing the effect of a light source on the color appearance of objects, compared to a reference source of the same color temperature (CCT). The highest CRI attainable is 100. Originally based on an eight standardized color comparison, it was later extended to fourteen colors.

Color Temperature or Correlated Color Temperature (CCT) - the color temperature of a light emitter refers to the temperature to which one would have to heat a “blackbody” source (Planckian radiator) to produce light of similar overall appearance or chromaticity. A low color temperature implies warmer color (more yellow/red) light while high color temperature implies a cooler light (more blue). The standard unit for color temperature measurement is expressed in Kelvin (K).

Dedicated, Positive, Interconnect System - provides small, fast and efficient connection from fixture to fixture utilizing a three cord, male and female connectors.

Footcandle - the unit of measure for the density of light on a surface unique to the USA. One footcandle is equal to one lumen per foot (lm/ft²). One footcandle = 10.674 lux.

 General Lighting (Ambient Lighting) - lighting designed to deliver a predominately uniform level of light throughout an area.

Grounding - all commercial fixtures are required to have a ground wire for a UL listing.

Initial vs. Mean Lumens - the measured luminous output of a new light source versus the output at 40% of lamp life.

Inline Cord Set - a switch that is wired onto the powder cord.

Kelvin - the kelvin unit is the basis of all temperature measurement. In lighting, Kelvin is the unit of measure for Color Temperature used to indicate the overall color of the light produced from a source.

Kilowatt Hour (kWh)- the measure of electrical energy from which electricity billing is determined. For example, at the rate of $0.10 per kWh, a 100 watt lamp operating for 2000 hours will $20.00 (100 x 2000/1000 = 200 kWh x .10 = $20.00)

Lumen (lm) - sI unit of luminous flux emitted within a unit solid angle (lsr) by a point source having a uniform luminous intensity of I cd. – or – The SI unit for measuring the flux of light being produced by a light source or received by a surface.

Luminaire (light fixture) - complete lighting unit which consist of lamp(s), ballast(s) – if applicable – as well as mechanism for light distribution, lamp protection and alignment and connection to power.

Luminous Efficacy - the expression of efficiency in converting power (watts) into light (lumens). Expressed as lumens per watt or l/w.

Rated Average Life - the length of operation (in hours) at which point an average of 50% of a large sample of lamps will still be operational and 50% will not.

Task Lighting - lighting designed for a specific visible operation which requires higher light levels; most often characterized by proximity to that task.