Glossary of Terms for Black Bros. Co. 2013

Transcription

1 Roll Coating Equipment Roll Coating is a means of applying an accurately controlled film of a liquid to various flat substrates, or to the top surface only of various embossed products. This includes adhesive or glue for laminating purposes as well as a variety of liquid coatings where application rate is important for performance or economic reasons. Coil or Web Coater This may be only a two roll head, to coat one surface of material in web form, or may incorporate two sets of rolls to coat both top and bottom surfaces of the web. Usually web tension maintains the contact between the coating roll and the stock. These are generally Reverse Roll Coaters, but a Direct Roll Coating approach may also be used. DRC Direct Roll Coater, applies liquid adhesive or coating from a roller to a substrate with the roll going in the SAME DIRECTION as the substrate, usually in sheet form. A Glue Spreader is a DRC with grooved applicator rolls for adhesive application. DDRC Differential Direct Roll Coater, similar to a DRC, but uses a variable speed Doctor or Metering roll to apply a smoother, more controllable film thickness to the stock. May utilize a finely grooved applicator roll to apply a specific amount of coating. Hot Melt Adhesive Spreader This is used to apply a heated product, usually an adhesive, by using heated rolls to keep the material in a molten state during application. Some type of heating system is also supplied as part of this unit. Panel Cleaner This is used for wood products in sheet form. It consists of one or more counter- rotating brushes to remove dust or chips from the surface of the stock, along with a vacuum pickup arrangement to assure a clean surface for gluing or coating. PRC Precision Roll Coater, this also is similar to a DRC, but it uses an engraved Doctor roll to more uniformly control the amount of material applied. RRC Reverse Roll Coater, applies liquid adhesive or coating from a roller to a substrate with the roll going in the OPPOSITE DIRECTION as the substrate can be used for certain types of sheet materials, but generally used for material in continuous web form. RRFM Reverse Roll Filling Machine, used to apply a heavy bodied liquid material to substrate in sheet form to fill minor surface irregularities to prepare for later finishing or laminating operations. Applies the coating as a DRC, but also has a Reverse Wiping Roll to smooth material into the surface of the stock while removing any excess. Laminating Equipment Various Platen and Roll Type laminating equipment follows. Air Pod Press A low to moderate pressure (10 to 80 psi) press, widely used for laminating HPL to Particleboard, Hollow Core Doors, and different foam or corrugated materials. Pressure is applied by inflating air pods. Spacing of air pods across the platen area determines the pressure applied. Heated Platen Press, Air Pod A type of air pod press using heated platens to hasten the cure of the glue line when laminating sheet materials. Platen pressures are usually from 50 to 80 psi. Heated Platen Press, Hydraulic (Hot Press) A press that uses heated platens to cure the glue. Pressure is applied through the use of hydraulic cylinders. Applies low to moderate pressure or can be designed to exert 100 psi or more across the entire platen. Offers longer platen stroke than an Air Press. Laminate Indexing Station This device allows laying up sheets of laminate to substrate with a minimum of manual labor. A transfer mechanism brings the sheets of laminate over the glued stock so they can be handled quite easily. A stack is formed which can then be placed in a platen press. A different version of this is available for use with the Panel Express system for lay-up of individual panels. 1

2 Panel Express A system that bonds products such as HPL to Particleboard in a continuous operation by using a combination of heat and pressure rolls. This is very effective for producing flat panels of differing lengths, as opposed to using a platen press. Rotary Press Also called nip or squeegee rolls, commonly used for laminating an overlay in roll form to substrate, (usually in sheet form). Pressure is applied thru air cylinders, which load the top roll. The rolls are usually rubber covered, but in some cases may be metal, either chrome plated or covered with Teflon tape. The rolls may be either room temperature, or heated, depending on the specific application and adhesive used in the laminating operation. Gluing and Coating terms: #/MSGL a term used to express glue spread in pounds per 1000 sq.ft. of glue line. Commonly used in the woodworking and furniture industry. Determined by weighing (in grams) the amount applied to a one sq.ft. piece of stock and multiplying by 2.2, i.e. 10 grams per sq.ft. x 2.2 = 22 #/MSGL. Adhesion The bonding together of two or more layers using some type of glue, or adhesive. This relies on both chemical and physical bonding between the pieces being laminated. Also refers to the bonding of a paint film to the surface being coated. Brookfield Viscosimeter A means of measuring viscosity by the resistance to flow (or shear) between a moving and a stationary object, i.e. a paddle or a cylinder in a cup. Catalyst An agent that causes a chemical reaction to occur. Catalysts can be used in both adhesives and coatings to aid in cross linking the product, giving better end use performance. Cross Linking An adhesive that cures chemically to form a bond that is resistant to heat and moisture. EVA Adhesive An ethylene vinyl acetate copolymer, often a Hot Melt. Provides quick bonds, but lacks high temperature resistance. Flow Out The ability of a paint film to smooth out after application. Hot Melt Adhesive This adhesive needs to be heated and applied in molten form. Cooling then solidifies the adhesive and effects the bond. Some hot melts are moisture curing, which means they further cure with the moisture in the materials being bonded. Mils a term indicating the wet film thickness of the material applied. One mil is 1/1000 of an inch. While generally used for measuring paint films, can also be a quick way to check glue spread. With an adhesive weighing 9 pounds per gallon, one mil is equal to about 5.6 MSGL. (MSGL/5.6 = mils) MCU Moisture Cured Urethane, an adhesive, but the term is also applied to coatings, where moisture, either in the materials being bonded or in the air, acts as a catalyst to cause cross-linking. Orange Peel A rough paint surface, similar to the peel of an orange. PVA Adhesive An emulsion adhesive of Polyvinyl Acetate, known as white glue. There are many versions of this type of product to meet a wide variety of end use requirements. PUR Polyurethane Reactive, a type of polyurethane adhesive that is applied at an elevated temperature, acts as a hot melt, then cures through the action of moisture in the materials being bonded. Silicone Coatings A liquid solution or dispersion of silicone applied to a surface to change the surface characteristics. Widely used on plastic films to give release or non-stick properties. Solvent A liquid that can dissolve another substance. 2

3 Solvent Coatings A coating or adhesive wherein the solids are dissolved as a solution, as opposed to an emulsion. Require cleaning equipment with a solvent. Thermoplastic An adhesive that, while solid at room temperature, will soften with the application of heat. Can still have many uses, as temp required to soften will vary with specific adhesive. Thermosetting A type of adhesive that cross links to form a permanent bond. Usually comprised of a resin and a catalyst, or setting agent. Viscosity An indication of the thickness or consistency of material resistance to flow water is low viscosity, molasses is high viscosity. Viscosity Cup A small cup used to measure viscosity by timing how long it takes for the material to flow from a certain size opening. Water Based Adhesive or Coating Any liquid product where solids are either dissolved in water or carried as an emulsion. These products can generally be cleaned from equipment with water. Laminating Terms: Batch Operation An operation where a batch of materials is processed through one operation, then the entire batch is moved on to another operation. Fast Tack An adhesive that quickly develops a bond, usually high solids product. Glue Line Area The actual contact area between two opposing surfaces. Many products, such as Hollow Core Doors, may have a glue line area much less than the overall surface area. It is important to consider this to avoid excessive pressure over the glue line area. Green Strength The ability of a glued assembly to acquire a good percentage of its final bond strength shortly after pressure is applied. Particularly valuable when bonding materials that resist lying flat, or to allow edge trimming shortly after laminating. High Solids This term is usually applied to PVA type glues. Many of these are lower than 50% solids by weight. Glues above this range are typically classed as high solids and generally exhibit greater initial tack and quicker curing. Inline Process An operation whereby a product goes from one operation to another with no interruption in the flow. Moisture Content The amount of water found in wood. Expressed as a percentage of its oven-dry weight. (Weight of water lost from a fully dried sample/weight of fully dried sample x 100 = MC) Usually measured with a two-pin type moisture meter. 6 to 8% is a typical range for laminating purposes. Freshly forest-cut green wood may have a moisture content of 30% to 100%, depending on the species and time of year cut. Before using any wood, it needs to be dried to reduce its moisture content. The ideal moisture content depends upon the use of the wood and the annual average relative humidity at the place where the wood is to be used. It is critical that the wood you work with be dried down to an MC within 2 percentage points of the equilibrium moisture content (EMC) of the in-use location. The EMC of air is numerically equal to the MC that will eventually be attained by any piece of wood when stored indefinitely at a particular humidity. Temperature has no direct effect on MC or EMC. The relative humidity (RH) in most homes and offices in the U.S. (except in coastal areas and the exceptionally dry areas like the desert Southwest) averages 30 to 40% RH. This is 6 to 7% (see Figure 1), which means that wood in interior locations will average 6 to 7% MC. Therefore, lumber intended for interior use should be dried to 6 to 7% MC and should be kept at this MC prior to and during manufacturing. 3

4 pli Pounds per lineal inch, used to express the laminating pressure exerted by a Rotary Press. An 8000# capacity Rotary Press can exert 130 pounds per inch of width across a 5 wide panel. psi Pounds per sq. inch of laminating pressure, determined by the capacity of the laminating press and the glue line area of the product being laminated. A 4 x 8 50 PSI Air Pod Press will develop 216,000# of pressure. This could apply a little over 60 PSI on a 3 x 8 load. Shear A load placed on a glue line parallel to the glue line, i.e. a piece of tape being pulled down a wall. VOC Volatile Organic Compounds are the solvent components in a finish. 3D Laminating Terms: 2 Chamber Press Not all membrane presses are 3 chamber machines, some positive pressure membrane presses are known as 2 chamber presses. In other words, there are only two pressure areas in the machine, i.e., there is a chamber below the 3DL where a vacuum is pulled, and there is a chamber above the 3DL where positive pressure is applied. 3 Chamber Press An advanced positive pressure membrane press functions as a 3 chamber machine, i.e., there are three chambers; one chamber below the 3DL where a vacuum is applied, one chamber in the middle (between the 3DL and the membrane) that has both vacuum and pressure, and a third chamber above the membrane that supplies positive pressure. 3DL 3D laminate, or more affectionately known as rigid thermal foil (RTF), However, it frequently is called by the following names: film, foil, thermofoil, laminate, or just vinyl. Most 3DL s in North America are vinyl, but there is a growing trend toward PETG (a thermoplastic resin of the polyester family, known as polyethylene terephthalate). 3D Adhesive see PUD. 3D Laminating Press see Membrane Press, Positive Pressure, and/or Vacuum Press. Activation Temperature All 3D adhesives are heat activated. The activation temperature is the temperature at which the adhesive activates in order to make a bond. 3D adhesives are sprayed onto the part(s), flashed off, and then the parts are placed into the press for processing. Adhesive see PUD. BAR BAR is a term used to indicate pressure. 1 BAR is equal to approximately 1 Kg/cm 2 or in American Standard terms, equal to about 14.5 psi. It is relative to the vertical column of weight (atmospheric pressure), at sea level, exerted upon a surface. Blow Out During pressing the 3DL can be breached for a number of reasons, commonly termed a blow out. Blow outs come in two varieties, a cold blow, and a hot blow. A cold blow is typical of too little heat in the process, and can be identified by a jagged, or torn edge to the 3DL. A hot blow is indicative of too much heat in the process, and can be identified by a stretched out, or elongated tear with smooth edges. Bridging Bridging occurs where the 3DL does not make contact with the substrate and bridges the profile. Typically it occurs on areas of the profile that are too tight to allow the membrane/material to make contact with the adhesive. Delamination The result of the 3DL releasing from the adhesive. This occurs under several circumstances, here are a few; 1) the activation temperature of the adhesive may not have been reached during the laminating process, 2) the adhesive may be starved/light at the point of contact, 3) improper treatment to the surface of the board these are just a few, and the more common issues. 4

5 Dog Ear See Pleating. Fatty Edge Typically created during the cycle when pulling initial vacuum. This is mostly associated with pre-applied adhesives, where the adhesive will bunch up at an edge, due to the stretching of the 3DL in a motion that scrapes the adhesive off the 3DL, and deposits it directly at the edge on the top/horizontal surface of the component. Film/Foil see 3DL. Halo/Haloing A visual indication, on the surface of a component that shows a distortion of the surface finish. This is usually created by too much heat in the process, whereby the outer topcoat starts to deteriorate, and the surface takes on a higher luster. Heat Tape To insure accurate reactivation settings, a product called heat tape can be very instrumental. It is a heat sensitive, self-stick, Thermolabel that is applied to the area where you want to test the heat source. It is important to note that it is usually applied right at the bottom of the vertical edge of the component, closest to the bed of the machine, in order to see what the temperature is at the most vulnerable point of the glue line. Membrane The membrane in a membrane press is mounted against the heating platen, and is used for two purposes, 1) to assist in forming the 3DL around the component, and 2) to bring a consistent heat source to the surface of the substrate. It is usually 1/8 in thickness and composed of either a natural or silicone rubber, the latter being the more common. Membrane-Less A process in a membrane press where you apply surface pressure by air only, without the assistance of a membrane. This is often used to gain greater definition on the surface. Orange Peel A term used to describe the surface appearance in high gloss laminating. The surface of the 3DL takes on a characteristic like that of the surface of an orange. This is typical of overheating during the process of laminating high gloss. Pedestals A term used to describe the item needed to raise a component off of the tray during the cycle. There is a wide range of names used to describe this part, such as; template board, riser, cull board, lift, pattern board, chair, spoil board, etc. Pillowing/Ballooning The release of 3DL from a routed area of a component, typically a result of either having a wet glue line, or not cooling down the part enough before release. Pin System An automated system that eliminates the use of pedestals, template boards, etc. Pleating The imperfection created typically at the corners of parts where the 3DL bunches up on the vertical surface. It can also be called a dog ear or wrinkle. PUD Polyurethane Dispersion, the type of adhesive used for 3D laminating. PUD s in the 3D process are water-based, and applied by using a spray gun system. Reactivation Temperature The temperature at which an adhesive will release from the substrate. Telegraphing A term used to describe the transfer of surface imperfections showing through to the top surface in a component. Usually telegraphing refers to foreign objects, i.e., hair or dust, or the original surface of the substrate. Tray This refers to the part of the machine that holds the components during the cycle. Common Substrates and Overlays: 5

6 Backer sheet A sheet glued to the backside of a panel to give it dimensional stability, commonly a wood veneer or a non-decorative sheet of HPL although different materials and even liquid coatings have been used for this purpose. EPS Expanded polystyrene is used as a core material in insulated panels; such are used for housing or refrigerated warehouses. Low density, about 1 pound per cubic foot. Hardboard Masonite was one of the original hardboards. This is made of fine wood particles, formed into a mat with adhesive and pressed to make a dense product, usually 1/8 to ¼ in thickness. The density is about 60-65#/cu.ft. Hollow Core Doors or another product having a non-continuous or hollow core, such as honeycomb. HPL High Pressure Laminate. This is formed with various layers of paper, impregnated with a resin, then pressed to form a durable product, widely used for kitchen countertops, dinette tables, etc. The top layer is usually a decorative paper, but some non-decorative products are also used in the electronics industry. Loose Lay-up The assembling of the portions of a hollow core door using loose stiles and rails, along with the lock blocks and honeycomb core. An experienced crew can produce a good quality door using this manner of assembly. MDF Medium Density Fiberboard is also about 45#/cu.ft., but the particle size is small, which gives it a better surface and edges for finishing or laminating. Melamine This term is often used to refer to HPL since the top or wear surface is a melamine resin. Melamine can also be a type of adhesive. Non-Woven Products Generally similar to a fabric, but not constructed in a regular interlaced pattern. OSB Oriented Strand Board is another engineered wood product made of large oblong flakes of wood, bonded with a waterproof adhesive, to compete with exterior plywood. The species of wood used to manufacture this is generally faster growing than that used for plywood. Particleboard An engineered wood product, made up of various size particles, of differing shapes, used for core material in many furniture operations. Weight is about 45#/cu.ft. Plastic Films Various types of films are available to meet different end uses, in general they are handled similarly to vinyl films. Pre-Impregnated Papers Paper treated with a resin to give better physical and wear properties. Widely used for some types of wall paneling and lower end furniture panels. SIP Structural Insulated Panels, commonly OSB laminated to both surfaces of EPS core material using a two-component polyurethane adhesive. As the name implies, these panels exhibit both insulating and structural values. Solid Core Doors or other panels having a facing sheet and a backer sheet over a continuous core. Stiles & Rails Generally used to describe the vertical and horizontal portions of a hollow core door. TFL Thermally Fused Melamine, a product consisting of a particle board, or MDF core, laminated with a decorative paper and melamine resin sheet. The two are fused to the core without any additional bonding agent. The melamine resin sheet penetrates through the decorative paper to bond/fuse to the wood core. Vinyl Film A PVC film, usually decorative, used as an overlay for kitchen cabinets and RTA furniture, also laminated to metal for cabinets for household appliances. 6

7 Visco Elastic NASA memory foam, also called visco-elastic foam, was developed for the space program in the 1970 s, although it was never actually used in the shuttle. It was created as a material for the astronauts flight chairs, to help reduce pressure points caused by the G-forces generated during lift off. A few years later, it entered the medical field for use in hospital beds, and before long, it was showing up in people s bedrooms. New technology and production processes have solved many of the old problems, like heat buildup and durability, and now memory foam can be found in homes around the world. Wood Veneer Solid wood that has been cut into very thin sheets, from 1/85 to 1/8 usually. Most veneer, especially in the thinner varieties, is highly decorative and used over Particleboard or MDF for fine furniture or paneling. Thicker veneers are used to make plywood and are laminated cross-grain to enhance performance qualities. Miscellaneous Technical Terms: BTU British Thermal Unit, a measure of heat, like a calorie, but of much higher magnitude. CFM Cubic Feet per Minute, used to describe air requirements to operate power tools, ventilate an area or collect dust from a woodworking operation. Coating to Doctor Roll Ratio The surface speed differential between the coating or application roll and the metering or doctor roll. On many Black Bros. machines this ratio is 6:1 and this allows a more even doctoring or metering of the material being applied. F.P.M. Feet per minute, typically describing line speed. Kw Kilowatt, 1000 watts, also 3412 BTU ROI A roll opening indicator used to express the opening between two coating or laminating rolls. Roll Deflection The bending of a roll caused by a load, either from an object passing under the roll or from the hydraulic force of a liquid between two rolls. This increases with speed. Causes a variation of pressure across the roll or results in an uneven coating. T.I.R. Total indicator run out. A measurement of the total variance in the surface of a roll as measured by a stationary mounted dial indicator. Electrical Terms: 24 Volt Control A control circuit operating at 24 volts, rather than at full line voltage, used to provide a greater degree of safety for the machine operator and for better control circuit versatility. 110-volt control circuits are also fairly common. Amp Draw The current drawn by an electrical motor or heater, commonly described in amps. Belt Case A variable pitch sheave arrangement to change the input speed from the motor to the reducer. Other mechanical devices may also be utilized. Direct Drive Driving a roll or set of rolls directly from the output shaft of a reducer to give a smoother operation than may result from an external chain or gear drive. Drive That portion of a machine that provides power to turn the rolls and propel the stock through the machine. A drive commonly consists of a motor and a reducer, and often a belt case or mechanical speed change device. 7

8 Explosion Proof Equipment with cases designed to operate within an atmosphere of explosive vapors and capable of containing any explosion that may occur within it. Inverter An electrical device that converts direct current (DC) to alternating current (AC), the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits. Motor The rotating electrical portion of the drive. Reducer That portion of the drive that reduces the speed of the motor to the rotational speed necessary to operate the machine at the proper line speed. Relay A solenoid commonly used in a control circuit. Reset Button A momentary push button used to reset a tripped relay or over current device. Solenoid An electrically controlled switch to control the flow of power to a motor. Without Controls & Drives Occasionally a machine is furnished in this manner where another party is going to supply the controls and drives to better fit in with the overall electrical package within the plant. Equipment maintenance can also be a factor for having one contractor supply all of the drives and controls. Water Tight Equipment with cases constructed to prevent the entry of moisture. Rubber Rolls Rubber covered rolls are an important part of many Black Bros. machines. They allow applying a controlled amount of glue or coating material, as well as applying pressure for various laminating operations. A few of these rolls, and their usage follows. Buna N This is another general-purpose covering. While some rolls may be grooved, many are used as smooth rolls for applying various oils, such as for metal drawing operations or for tempering hardboard. They have relatively good heat resistance, and are resistant to certain solvents that may attack Neoprene. Double Sleeve Rolls This is a special type of construction, consisting of a soft base, or cushion material, covered by a harder outer sleeve. This is done to allow for variation in the thickness of the stock being coated without changing the amount of coating being applied. While quite useful for certain applications, the higher cost of this roll needs to be considered. EPDM Also use for coating rolls, especially with active solvents, such as Acetates, Ketones and Ethers. The surface is normally ground smooth, but for certain applications, a fine grooving may be used. Neoprene Rolls of Neoprene are perhaps the most widely used rolls in Black Bros. equipment. They are durable, but yet can be ground and grooved cleanly, that is, without tearing. Grooved Neoprene rolls have been used for years for applying many adhesives in the woodworking industry. Grooves that are ground into these rolls, and the hardness of the roll itself, help to attain the proper application rate. Generally used for water base products and at room temperature. Silicone This polymer has found great use in applications involving heat above 250 degrees. Specifically in the application of Hot Melt PUR adhesives. In addition, the release properties of this compound help in cleaning difficult materials from the roll surface. Urethane Rolls made of cast Urethane are used for application of various paint coatings. They have good solvent resistance to the Aromatic Solvents, like Toluene and Xylene, and the surface can be ground very smooth to assure a good lay-down of material. 8

9 Roll Construction Nomenclature: Core The main tubular element giving the roll a diameter and length. Flange An extension (in diameter) to the plug that is milled to retain the covering of a roll. Journal The area of the shaft that rides in the bearing. Keyway A milled area on the shaft that holds a key, to index the shaft into a sprocket/gear. Plug The end plate of a roller, which both accepts a welded shaft, and in turn gets welded to the core. Shaft The horizontal extension of a roll that is milled for bearing journals, sprockets, and gear assemblies. The shaft is welded to the plug to form a plug/shaft weldment that gets welded to the core. Shoulder The area of the plug where shaft meets flange. Wall thickness Indicates the thickness of the core, measured in inch increments. Rubber Roll Nomenclature: Chevron Rolls These rolls have a pattern cut into the surface to allow the action of the roll to expand a web of material as it passes over the roll. The pattern is usually cut into the roll in a left hand right hand pattern, starting at the center of the roll surface. Perhaps less costly than the Mt. Hope roll, but they can induce lines in the material being spread if the web tension is too high. Composite Grooving Composite grooving consists of both a Helical Grooving and a Longitudinal Grooving. Sort of like a crosshatch. This grooving is usually based on a V shaped groove and is useful for applying adhesive to solid stock, such as particleboard core stock and the stiles and rails of hollow core doors. This pattern allows using more pressure than the Helical Buttress grooving without getting wring-off at the end of the stock. Duro This describes the hardness of a roll. It is generally measured using a portable instrument called a Durometer, using the Shore A scale. Coating rolls are in the 20 to 50 Duro range and glue spreader and laminating rolls are about 65 Duro. Expander Rolls Typically referred to as a Mt. Hope roll (one of the primary manufacturers). This roll uses a bowed shaft on which is placed a series of bearings, which are covered with a rubber sleeve. As the surface of the roll revolves, the sleeve expands along the length of the roll to smooth out a web of paper or vinyl as it passes over the surface of the roll. Very effective. These rolls are available in both a fixed-bow and an adjustable-bow version to meet different requirements. Chevron rollers are usually supplied for rigid webs like paper and Mt. Hope are for flexible webs like vinyl or foam. Ground and Polished Some rubber rolls used in critical coating operations are first ground smooth, using an abrasive wheel or belt, then hand-polished using a fine grit paper to obtain a very smooth surface finish. Helical Grooving This is actually a thread ground into the surface of the roll. The pattern of the groove, along with the coarseness and the depth determine the range of coating thickness that can be applied. Most groovings are in the range of 8 to 28 threads per inch. Buttress shaped grooves are used for applying wood adhesives to veneer stock. Chrome Plated Rolls Chrome plated rolls are used for various purposes, doctor rolls, feed rolls and, in some cases, coating rolls. Here are some of the various surface treatments used. 9

10 1N-2CP This uses a.001 layer of Nickel under the.002 of chrome to provide a greater barrier from corrosion due to the chemical nature of the coating or adhesive. Used on many Glue Spreader doctor rolls. 1N-5CG As above, this uses a.001 layer of Nickel under the.005 chrome coating to provide maximum corrosive protection and still allows the surface to be ground to obtain an accurate surface. 2CP This is.002 of Chrome Plating on the surface of a roll, used to eliminate rusting or mild corrosion. May be used on doctor rolls where severe corrosion is not a problem. 5CG This amounts to an average of 005 of chrome, to allow the surface to be ground to attain minimum TIR. A good application for doctor rolls used with smooth coating rolls for paint or coating applications. Also used as a coating roll for Reverse Roll Coaters for web stock and as the Reverse Wiping Roll on a RRFM. Engraved Rolls Some doctor rolls are mechanically engraved with a fine pattern to apply a specified amount of coating material. See Precision Roll Coater. Rotates at a 1:1 surface speed ratio with respect to the coating roll. Flash Chrome This is perhaps the lightest application of industrial chrome. It is economical, gives a good appearance, allows easy cleaning and is useful where the surface demands are not great. Conversion Factors: Electrical: Pressure: 1 Kilowatt = 3412 BTU 1 Horsepower = 746 Watts 1 Bar = 1 Atmosphere (approx) = 14.5 psi 1 Bar = 1 kg/cm 2 Length: 1 Meter = milimeter =.0394 (39.4 thousandths) 1 Inch = 25.4 mm Weight: Temperature: 1 Kilogram = 2.2. Pounds 9/5 x C + 32 = F / or 1.8 x C + 32 = F F - 32 x 5/9 = C / or F 32 x