MASS FINISHING TECHNICAL8 - Metal and Composite Finishing Equipment

MASS FINISHING

Mass finishing is a process that automates the mechanical and chemical finishing of non-fixtured complex shaped parts.

Mass finishing utilizes many types of energy generating equipment, abrasive medias and compounds that transmits the energy from the equipment thru the media to the parts being processed. The machinery energies the media to move in a random or precise flow around, into, and thru the parts being finished.

The process can be wet or dry and will run a multitude of parts and processes at a time. Mass finishing can obtain repeatable results with a low cost per part.

Process capabilities of Mass Finishing

Mechanical Visual

Deburring and edge radiousing Uniform finishingSurface refinement BlendingSurface roughing BrightingPre paint adhesion Cleaning Peening Satin FinishingStress relieving Matte finishingRemoval of tooling marks Pre plate and anodize finishing

Factors that affect the mass finishing are:

1. Equipment2. Media3. Compounds

1. MASS FINISHING EQUIPMENT

MASS FINISHING TECHNICAL INFORMATION

There are a number of choices when selecting equipment for mass finishing. There can be a lot of overlap where various machines will accomplish the same finishing process results. Other factors to look at when choosing the right equipment will be: labor available to assist equipment processes, time available for finishing process within the cell or production cycle, capital, the part being processed, and other processes that can be incorporated (part unloading, washing, rinsing, drying, inhibiting,etc) into the equipment to reduce labor.

Equipment available in the mass finishing industries.

A. Vibratory machinesB. High energy systemsC. Specialty mass finishing systems

A. VIBRATORY EQUIPMENT

The energy that vibratory systems generate is derived from a 1200 to 3500 rpm electric motor rotating a eccentric weighted shaft. The shaft is attached horizontal to a tub vibratory machine or vertically to a bowl vibratory machine. The weighted rotating shaft generates a vibrating action that is transferred to the machine. The vibratory machines action vibrates the abrasive media (which is contained within the urethane lined u shaped channel of the machine) impacting the parts being processed within the media.

Energy level low to moderateMedia action Vibrating punching rolling action measured in millimeters of amplitude ranging from 1 to 8 mm, with 3-6 mm the normal operating range.Applications general deburring and finishing of machined parts, stampings, castings weldments and composite surface prep.


Tub Vibratory equipment

Tub vibratory systems are comprised of a rectangular u shaped tub. The tubs can have various channel diameters and channel lengths. The tub is mounted and suspended on springs attached to the base of the machine. The motor and rotating shaft is located within the base. The shaft is attached to the bottom of the tub and run by a v-belt drive from the motor attached to the base.

Advantages Disadvantages

Long part processing Manual part unloading

Easily divided, for running Small flat parts stick to thelarge parts that cant touch tub side walls.or different medias at one time Parts migrate to the drive end Smaller systems inexpensive of the tub decreasing media to and portable part ratio.

Large systems can be built forcontinuous automation

Bowl Vibratory Equipment

Bowl vibratory machines are comprised of a donut shaped u channel tub. The bowl can have various channel sizes and overall diameters. The bowl is held suspended by springs that are attached to a round base. The eccentric shaft is mounted vertically thru the center column of the bowl. The motor can be in the base running the shaft by a v-belt drive or in some machines the motor is built around the shaft mounted within the center column.

Advantages ! Disadvantages

Internal part unloading and Restrictive on very long partsmedia separation

Less part to part damage Mid level and up on capital investment

Secondary operations such as media classification, part rinse, cleaning and dryingCan be built for batch or continuous automation


B. HIGH ENERGY MACHINES

Centrifugal high energy is a controlled centrifugal rotation of a disc or barrel creating an acceleration and de acceleration and a compressive flowing media action. The centrifugal finishing processes 7-20 times the energy of vibratory machines. The centrifugal high energy is not only is faster, but it also produces superior finishes than the media punching action of the vibratory machines.

Energy levels high to very high- up to 20 times the energy of vibratory machines

Media action Controlled centrifugal flowing compressive action

Applications Super finishing, Deburr of small parts, good for flat part separation while processing, Drives small media into small areas with energy.

Centrifugal Disc Machines

The centrifugal disc(CD) utilizes the energy of a 100 to 200 rpm rotating disc at the bottom of a bowl container. The rotating disc accelerates the media to a stationary side wall which de accelerates it and then gets re accelerated back and down to the center of the disc. The continued media acceleration and de acceleration flow produces energy 7-15 times that of a vibratory machine. The CD machine is one of the few hight energy processes that can be automated.


High energy Higher capital investment

Easily automated Ring and rotor wear life costs approximately $1.00 per operatingFlow thru water system for reline costsQuick time cycles for cellularmanufacturing Large and heavy parts process numbers low because of part on part damage.Run wet or dry


Centrifugal Barrel Machines

The centrifugal barrel (CB) equipment looks and operates like a ferris wheel with a cover. The energy is produced by a 100 to 240 rpm rotating turret with (generally 2-4 hexagon or octagon barrels) built within the turret that counter rotates at various rpmʼs . The action of these fully enclosed high speed rotating barrels produce a compressive sliding grinding action. The CB produces the highest mechanical mass finishing process at up to 20 times the energy of vibratory finishing.


High energy Very time consuming to load and unload barrels.Can run dividers in barrels to keep parts from damaging Cannot be automated

Very short time cycles Batch processing only

Run wet or dry

Part radiusing up to .030 C. SPECIALTY HIGH ENERGY EQUIPMENT

Magnetic Finishing equipment

The energy from magnetic equipment is derived from rapid rotating magnets built under the tub container holding the parts and media. The changing polarity of the magnets run at very high speeds drive the magnetic stainless media within the tub to a very aggressive spinning action.

Energy level Very high

Media action High speed spinning of stainless pin and various shaped medias

Applications Removes burrs from tiny holes, slots, knurled parts, and hard to get thread burrs. Works on non ferrous parts. Highly magnetic steel parts do not work because they move with the magnets.


Chemical Finishing

The chemical finishing process(CF) produces a high rate of material removal and super surface refinement (down to 2 RA) by oxidizing the surface of Ferrous ( iron based ) materials,some non ferrous processes also work. The chemical ( occolic acid, citric acid, or phosphates) continuously activates the process parts surface allowing a very heavy ceramic media (120 to 140 lbs per cu ft) to remove the material at much higher rates. The usually non abrasive media acts as the chemical carrier as well as the surface scrubbing agent.

The process produces a refined, bright finish with minimum edge radiusing. The CF process is generally used with bowl vibratory equipment but can be run in tubs vibrators, centrifugal disc and drag machines. All systems must use a very accurate compound delivery system. The low PH process chemical must be adjusted to normal discharge rates before flowing to sewer.The burnishing or brightening secondary compound(higher PH) step can be flowed into the same sediment tank as the process compound(lower PH) neutralizing for proper disposal.

Energy level Very high material removal

Media action Vibratory or flowing action basically carrying the compound and scrubbing the oxidized surface allowing for continuous re-oxidizing.

Application Refining gears, finishing hand tools, gun parts that require very little radiusing. Surface refinement and brighting within the same system. The advantages are low initial capital requirement for high energy. Best results for iron based alloys.

Spindle and Drag machines

The energy of the spindle equipment is generated by a stationary or rotating bowl of wet or dry media with a number of stationary or moving and rotating spindles that holds the parts into the media. The drag machines use the spindles to move or drag the process parts thru a dense non moving media within a tub. The dense non moving media creates a very high metal removal rate. The slight vibration of media reduces the machine horsepower require and introduces new media to the cut area.


The spindle and drag machines can run larger parts that are held or fixtured for a high metal removal, super burr removal or high luster finishing. Chemical finishing has been introduced with these systems to improve them futher.

Energy levels Very high

Media action Spinning by the part with spindle machines and densely laying in the tub for drag machines. Both utilize spindles or work holding devices.Application Turbines and propellers for high metal removal, high capital outlay.

Low Energy Systems

Barrels The barrel equipments energy is produced by a rotating hexagon or octagon shaped barrel where its design lifts the media and parts loaded within. The flat sides of the barrel lifts the media and process parts up for the slide down.The finishing action is taking place only on the downward slide. The operating rpm range of the barrels are from 15 to 30 with 17 to 20 being the most productive. Increases in rpm reduces the thickness of the downward slide. Media and part levels of 50% will create the longest slide. Barrel finishing in americaʼs industrial manufacturing sector started well before 1915.Vibratory machines replaced most barrel applications because it was quicker, more effective in internal areas of the process parts as well as easier to load and unload.Barrel finishing has its limited applications today and is highly used in jewelry production.

Energy Very low

Media action Sliding action only taking place on the downward movement .

Application Processing of small flat parts keeping them from sticking together while wet. Delicate finishing, very high luster capabilities. Some medias can start out cutting and end up finishing as they wear in barrel systems. Very time consuming to load and unload.


2. MEDIAS FOR INDUSTRIAL MASS FINISHING

The media transmits the energy generated by the mass finishing equipment to the parts being processed..Medias are capable of finishing in various ways.They can cut fast, remove burrs, edge radius, and rough up a surface for paint adhesion. Medias can also refine and smooth surfaces to low RMS finishes, burnish and clean.The systems energy moves the media in various ways. The media is one of the most noticeable elements to mass finishing but equipment energy and compounds are also very important.The industrial preformed medias are identified by there bonding agents (Ceramics and Plastics).

Consider the following when choosing a media for a process

A. Media TypeB. Media ShapeC. Media SizeD. Media hardness

A. MEDIA TYPE

There are basic media types used in industrial mass finishing, identified by their bonding agents.

CeramicsPlasticsSpecialty medias

Ceramic Medias are produced by mixing an abrasive ( commonly aluminum oxide, bauxite, silicon carbide, or quartz) with a ceramic matrix in a green(wet) state.The matrix (the consistency of damp clay) is extruded thru various shaped dies and then wire cut into small pieces. The green preformed media pieces are then fired at high temperatures thru a continuous or batch kiln for up to 24 hrs with precise heat up and cool down cycles. The harden ceramic pieces are then post tumbled to remove flash and packaged for shipment.

The different kiln firing temp control the medias hardness. Faster cut medias are designed to be softer allowing new cutting elements to be exposed. Polishing medias with no abrasives are designed to be harder to burnish the parts to be brighten. There are all cuts and hardnesses in between, so generally the slower the cut the harder the media.


The media clay matrix and abrasives also determine the finishing and cutting capabilities.The weight per cubic foot of ceramic media is approximately 85 lbs, with smaller sizes (1/4 “ and below) weighing approx 15% more. There is a light weight ceramic using light weight quartz as an abrasive with a high porosity ceramic matrix that weighs 55 lbs per cubic foot. There is also a high density ceramic media that is fired at higher temps to make them tougher and fracture resistance that weights up to 140 lbs per cubic foot.Ceramic medias hardness range between 45-65 rockwell. The ceramic medias abrasive grit sizes range between 80 grit (165 micron) and 220 grit (63 micron) with some dust collector fines down to 400 grit ( microns)

PROCESS CAPABILITIES OF CERAMIC MEDIAS


Burnishing (brightening) Can cause damage to softer materials

Heaviest burr removal and edge radiusing Some formulations can chip, causing of any mass finishing media Media lodging in small holes.

Many formulations available Further surface refinement below 12 ra requires high energy equipment or aHigh strength-long wearability secondary plastic media process.

Cleanest running media

Low density used for delicate parts

High density used for faster cut and less chipping

Produces a brighter scratchy matte finish

Good for surface roughening for coating adhesion

Chemically inert, Biodegradable, sewage dischargeablewith sediment removal recommended .

Quickly removes polish lines

Media attrition rates between .002 and .010 of total mass per hour


Plastic Medias are produced by mixing an abrasive( primarily a quartz, aluminum oxide, or silicon carbide) with a polyester or synthic based resin fluid with a catalyst added to harden the matrix. The matrix fluid is pored into multiple molds built into a tray and sent thru a heated curing process to harden. The media hardens quickly and then is tumbled to remove flash and packaged for shipment. Plastics are light weight, approximately 60 lbs per cubic foot for polyester and 50 lbs per cubic foot for synthetic. There is a high density plastic utilizing heavy zirconium sand abrasive that weighs approximately 100 lbs per cubic foot, this is used when fast cut but better finishes are required with a one step process. Plastic medias are much softer that ceramic medias. The bonding agent for polyester plastic are approximately 45 rockwell and the hardness on synthetic media are o brinnell, the softest of all preformed medias.

PROCESS CAPABILITIES OF PLASTIC MEDIAS ARE:

Produces surface refinement to 4 RA

Cuts light weight burrs without rolling them over

Softer and lighter that ceramic media

Good for processing delicate parts or softer materials

Produces a soft grainy matte finish

Media attrition (wear)rates between .0013 to .002 per cubic foot per hour.

SYNTHETIC PLASTIC VS POLYESTER PLASTIC

Advantages Disadvantages Advantages Disadvantages

Bio degradable Non bio degradable oil based - polySoftest of all preforms wears quickly higher wear rates

Runs cleanest of plastics High sediment sticking to partsBrighter finish requiring cleaning

Sediment settles quickly Sediment has samefor waste treatment specific gravity as water not allowing


Avail in high density good sedimentation

Random Medias can be man made such as the sintered ceramics for burnishing and the aluminum oxide nuggets for fast cutting.These medias are screened for size but are random in shape allowing processing in many areas of the parts. Radom medias can also include sand and river rock. There is some fast cutting and finishing applications ofthe man made random medias,however, not much for natural materials in industrial finishing.

Dry Process Media used most commonly are crushed and sized corn cob for part drying. Corn cob, walnut shells and wood pegs are also used for brighting with impregnated rouges and polishing pastes. Dry preformed plastic and composite medias have recently been developed and are run with dust collectors to remove the dust. Many mass finishing processes cannot allow the parts to get wet, this and high luster are two main applications of dry media. Running dry medias presents a challenge without the water cushioning the parts or cleaning the mass.

Steel Media is a steel or stainless product that is cold formed from wire, heat treated and then polished. Steel media are available in many shapes, they have precise measurements and wear very slowly with service life up to 10,000 hrs. The steel media weighs approximately 300 lbs per cubic foot, so machines have to be built especially to handle the weight. The applications for steel are burnishing, cleaning, peening for strength, and light deburring without media lodging in the part. Steel media processing has been extensively used in industrial finishing and deburring applications.


MEDIA SHAPE

The medias shape is designed and picked to reach into areas of the parts being processed that require work, while keeping out of other areas( holes, slots, etc.) to prevent the media from lodging within the parts.

The various shapes also have process significance. Flat sided medias ( tri angles,tri stars, and the ends of cones and cylindrical wedges) generate longer surface contact time on edges for deburring and radiusing. Round medias ( balls, cylinders, cones) generate a single point contact concentrating energy in one small point ( like a ball peen hammer)producing more work in that area. Round media shapes are are used in burnishing or part brightening. Sharp pointed media shapes can reach into difficult areas but are also prone to chipping causing media chips lodging in small holes or slots.

Common preformed media shapes and there uses Ceramic Plastic Tri Angles avail in straight cut and 22 degree angle cut. The angles provide greater penetration into remote areas while the flats have longer contact time on edges for deburring and radiusing. Standard and most popular shape for deburring. Its available in ceramics andPlastics medias. Ceramic Plastic Tri Stars are avail in 22 degree angle cut, designed with reaching in a bit more remote areas such as holes and slots than tri angles but also keeping the flats for longer contact time for deburring and radiusing. Its available in ceramics and Plastic media.

CeramicCylinders are avail in 22,45 and 60 degree angle cuts. The cylinder is designed to improve finishes with the round single point contact shape. The angles of cylinders are used to reach into tight areas. The cylinder rolls well in mass finishing and is a good choice for surface improvement in high energy centrifugal discs and barrels. The cylinder is one of the first choices for part burnishing


and brightening. Its only available in ceramic media

Ceramic Plastic

Cylindrical Wedge are used on a wide variety of parts. They have a cylindrical surface that mates well with concave surfaces. It also has two flat surfaces that perform well on convex surfaces, flat surfaces and edges. CW combines the strong points of triangles and cylinders to penetrate corners, slots and angles The CW rolls well in machines, minimizes many lodging problems and is a good shape for non chipping. Its available in ceramics and plastic medias

Ceramic Plastic Cones have flats for deburring and round areas for single point contact excellent for finishing. Cones roll good in mass finishing and is a good choice for parts without holes. Cones finish slots well. Cones are one of the first choices for surface refinement.Its available in ceramics and plastic medias

Plastic

Tetrahedron (tets) have points to reach difficult areas and flats for deburring, radiousing and extended surface contact. This is a good choice for mixing with tri angles for exterior surfacing with hard to reach areas. This shape is prone to some chipping of sharp points. It is available in ceramics and plastic medias.


Plastic

Pyramids uses the many angles of flats to finish flat areas and slots. Pyramids minimizes media lodging in holes. It finishes fast because of its shape and because it creates a lot of voids within the mass. Available only in plastic media

Plastic

Wedges is a uniquely designed shaped media that eliminates many media lodging problems. While its configuration will reach hard to finish inside corners, slots, and angles. This is one of the only media shape that sharpens as it wears. A good choice for complex machined parts. Only available in plastic media

Ceramic

Ellipse are used for surface refinement of hard to reach areas. Adaptable to many applications. Improves surfaces with extended media life. Used on finishing multi shaped turbine blades, heat sinks and slotted areas. Only available in ceramicMedia

C. MEDIA SIZE


Media size is an important factor in the selection of media for mass finishing. Larger media generates higher energy because of the mass of each piece(like a larger hammer delivers more energy to a nail) and the increased energy created by the voids within the mass that it creates . Larger media cuts and finishes faster with higher wear rates. Larger media suspends and supports larger parts.Smaller medias hold more water/compound which assists in cushioning the part creating less part on part damage. Smaller media have a gentler impact on the part which results in longer process time cycles, better finishes, and less media wear.Media sizing is also a factor with automated part unloading equipment utilizing mechanical screening of media/part separation. Generally medias have to be a different size (larger or smaller) than the part to utilize standard screening mechanical separation.The majority of mass finishing is accomplished with media sizes ranging between 1/4 inches to 2 inch. Burnishing medias ( brighting and cleaning) utilize smaller medias ranging from 1/16” to 3/8” for best results. Smaller media under 3/8” cost more because there is more labor and pieces per lb in its production, and media is sold by the lb.

D. Media Hardness

Media hardness is determined by the bonding agent. Ceramics are harder than plastics.

Ceramic media bondings will run between 45 to 65 rockwell hardness. Faster cutting ceramic media are bonded softer and designed to wear faster exposing new cutting abrasives elements. Medium cut medias are bonded harder than fast cut media.The burnishing or brighting(porcelain) medias with no abrasive added are bonded the hardestand have extremely long wear rates. Ceramic bonding strength and hardness is controlled mainly by the firing temp and dwell times within the kilns that harden them.

Plastic media bondings (synthetic or polyester) will run between o brinell (very soft) for synthetic and 25-45 rockwell for polyester.

Harder medias can damage softer materials being processed. Harder formulations can chip easier than softer medias becoming a problem lodging in small areas of the parts and in sewage discharge.

3. COMPOUNDS


Soap compounds are very important to the mass finishing process. Compounds are more often the success or failure of many processes. The mass finishing industry have developed hundreds of compound formulations that accomplish amazing results in many processes. Compounds developed for mass finishing are concentrated and are generally mixed 1 to 2 oz. per gallon of water. Flow rates of compound/water mixture run 1 to 2 gallons per cubic foot of the mass per hour for vibratory systems and 7 to 15 per cubic foot of mass per hour in high energy centrifugal disc systems. Small dense media masses and clean running ceramic medias require less soap/water flow than plastic medias.

Soap compounds accomplish the following

Cleaning the contaminations from the process parts and the media of; media sediment, oils, dirt, oxidation, rust, and descaling, is the compounds function. The compound holds the dirt in suspension allowing contaminates to be removed from the parts surface and carried out of the system, just like the soap in a households cloth washing machine. Maintaining the systems cleanliness keeps the finishing process stable and repeatable .

Inhibiting for rust and corrosion of parts while they are processed wet and keeping them inhibited post process is very important. Its essential that mass finishing process compounds have inhibitors in them. Maximum rust and corrosion inhibiting shelf life after a mass finishing process is obtained by a secondary post process inhibiter spray or dip.

Burnishing (Brighenting) of parts for or even brightening during deburring and surface refinement applications is primarily a compound function. Each alloy of metals; alum, brass, copper, steel, stainless or titanium etc) may require different surfactants that bring up its maximum luster potential.

Lubricates and cushions the media and parts extending media and machine lining life while eliminating part on part and media damage. Soap decreases media costs and reduces process time.

Special applications such as heat treat or mill scale removal, accelerators for surface refinement , and non keelator formulations for waste treatment systems.

Review of mass finishing process selection


The steps in selecting a mass finishing process is to determine:

1.The parts ( type, material, size)

2. The finish requirements of the part ( deburr, radius, surface finish, burnish, clean Rinse, inhibit, dry, etc.)3. The production rates of the part and flow thru the plant.

4. Labor available for the system

5. Capital available for the system.

6. What the part is costing currently to finish

7. Determine or eliminate various possible equipment required.

8. Send a number of parts to a finishing lab (usually the equipment manufacture your considering) and have them finish the parts to recommend equipment and medias to prove the process and production rates.

9, Then determine the equipment and then the finishing process costs.

DETERMINING MASS FINISHING PROCESS COSTS

A. How many parts per cubic foot can the system processB. Media and compounds costC. Cost per part

A. How many Parts per cubic foot is determined by a measurement of volume and an estamate of media to part ratio. Take the cubic inch of the parts and multiply it times the media to part ratio and divide into cubic inches in a foot = parts per cubic foot

1728 ______________________________ = Number of parts per cubic foot ( parts L” x W” x H” ) x (media/parts ratio)


Media to part ratio is determined by the parts size, shape and weight. The media protects the parts from damaging one another. Heavier,larger, sharp cornered parts are more prone to part on part damage requiring more media to protect them which increases the media to part ratio.

Below are estimates of required media to part ratio for various parts for mass finishing. Increased media to part ratio increases protection but decreases parts per cubic foot. Stampings, parts less than 9 cu/in 3:1 media to part ratioParts requiring self unload 3:1 “Castings with non critical surfaces 4:1Machined parts 4:1 “Parts requiring super surface refinement 5:1 “Longer parts to keep from jack strawing 5:1Larger parts with critical surfaces 6:1Larger parts with sharp protrusions 7:1Delicate parts that may tangle and damage 8:1

Parts that cant touch will need compartmentizing

Example: Calculation of Parts per cubic with a 3:1 media to part ratio

Part is a small machined part that needs self unloadMedia/part ratio estimate 3:1Part size 3” x 4” x 2” = 24” total cu/in of the part

x 4 (3:1 Media/parts ratio) = 96 divided into 1728 = 18 parts per cubic foot

Example: Size machine required

Take the parts per cubic foot, parts production rate, process time cycle, parts production flow, and you can determine the size of the equipment required.

at 18 parts per cubic foot if you need to produce 1800 parts per 10 hour shift at a 1 hour process time you would need a 10 cu foot size finishing system.


B.Media and compound costs in mass finishing

MEDIA COSTS PER PART

Machines cu/ft x media weight per cu/ft x medias attrition rate per hour x % of hour time cycle x cost of media per lb.( sold by the lb) divided by no of parts per cu/ft. EXAMPLE 1 cu foot machine - Media weight 85 lbs cu/ft - attrition rate of .001 - 1 hour process time cycle - $1 per lb media cost - 10 parts per cu/ft.

EXAMPLE MEDIA COST PER PART 1 cu/ft machine size x media weighs 85 lbs per cu/ft x hourly media attrition rate of .001 x 1 (hour) time cycle x $ 1.00 lb media cost , divided by 10 parts running per cu/ft =

1 x 85 x .001 x 1 x $1________________ = MEDIA COST PER PART 10

COMPOUND COST PER PART

Machines cu/ft x .oz of compound used per cu/ft per hour x % of hour time cycle x $ cost per .oz - divided by number of parts per cu/ft

EXAMPLE 1 cu ft machine - 1 oz compound per cu/ft - 1 hour process time - $ 7 gal or .06 .oz ( gallon price divided by 128 oz per gallon) - 10 parts

EXAMPLE COMPOUND COST PER PART 1 cu/ft machine size x 1 oz. compound per cu/ft per hour x 1(hour) time cycle x .07 per .oz compound cost - divided by 10 parts running per cu/ft =1 x 1 x 1 x $ .07 ___________ = COMPOUND COST PER 10 PARTMedia costing continued:


Information required for media costs:

Mass finishing media weight and hourly attrition (wear) rates per cubic foot

Media Type Weight Vibratory hourly attrition - High energy hourly attrition cu/ft Rates % Rates %

Ceramic-polish 85 lbs .0001 .0003Ceramic med cut 85 lbs .005 .015Ceramic fast cut 85 lbs .0075 .0225 Ceramic super fast 85 lbs .01 .03Ceramic high den. 120 lbs .01 .03Polyester plastic 65 lbs .013 .040Polyester high den 100 lbs .015 .045Synthetic plastic 50 lbs .018 .055Microbrite 110lbs .0001 .0003Steel & Stainless 300 lbs .0001 .0003

note: smaller medias 3/8” and under in size weigh approximately 15% more and have 25% less attrition wear rates than stated above.

C. Total Mass Finishing Cost per part


MASS FINISHING COST PER PART WORKSHEET

HOURLY EQUIPMENT PAYBACK COST

Equipment investment______ divided by numbers of amortized years_______

divided by hours per year________ = TOTAL EQUIPMENT HOURLY PAYBACK _________

______________________________________________________________________

HOURLY PROCESS COST

Equipment power cost_______ H.P. X .746 X .08 cents per KW = _________

Media cost_____ lbs per load X____ *hourly attrition rate X ____Price/lb _________

Compound cost_______.oz per hour X ______ cost per oz. = _________(Price per gallon divided by 128 = cost per .oz) TOTAL HOURLY PROCESS COST _________

______________________________________________________________________

PROCESS COST PER CYCLE

Total hourly process cost__________ + Equipments hourly payback X% of hours per load___________ = _________

Hourly labor rate________ X ________ % of hour of labor per load = _________

TOTAL PROCESS CYCLE COST _________

______________________________________________________________________ COST PER PART

_____Total Process cycle cost, divided by_____no of parts per cycle =

TOTAL COST PER PART _________

OVERVIEW OF MASS FINISHING EQUIPMENT AND MEDIAS


Equipment MEDIA

Vibratory Ceramic media Tub vibratory Polish-Burnishing

Bowl vibratory Medium cut

High Energy Fast cut

Centrifugal disc Light weight

Centrifugal barrel High density

Magnetic spin finishing Plastic media

Chemical high energy Polyester

Spindle equipment Synthetic

Drag machines Random media

Alum oxide

Dry process media Corn cob Walnut shells

Wood pegs Steel and Stainless


MASS FINISHING TECHNICAL8 - Metal and Composite Finishing Equipment

Documents

Transcript of MASS FINISHING TECHNICAL8 - Metal and Composite Finishing Equipment