Project To estimate the new shot blasting & painting facility for new project

Project Overview

Project Name : To estimate the new shot blasting & painting facility for new project.

Company Name: Godrej & Boyce Mfg.Co.Ltd.

Presenter Name: HARSHAD V.SURYAWANSHI

Project Goals

1.To estimate and create new Shot Blasting & Paint facilities for New Project Enercon

NEED The Need of the project: Existing Process : In the existing Process, shot blasting & Painting is

done in a close chamber where atmospheric conditions are not possible to control. Also there is no proper extraction system in the booth.

New Process: As per project requirement following atmospheric conditions are required to be maintained during Shot blasting & Painting process.

1. Relative Humidity : Less than 85%.2. Surface temp. : 3 deg. Cent. above dew point.3. Atmospheric Temp.: Above 5 deg. Cent. 4. Storage of the Coating material : Should be stored in cool place. 5. Dust free atmosphere during shot blasting & painting.

In the exiting set up, it is not possible to maintained all these atmospheric conditions. So to meet the project requirement, we design & construct a new Shot blasting & paint booth.

SHOT BLASTING AND PAINTING PROCEDURE FOR STATOR CARRIER 6 ARM1.After fabrication all temporary cleats and lug attachments will be removed and area under them will be ground smooth2.Degreasing:If the oil/greasy material available on the surface it should be removed by suitable degreasing agent followed by thorough water cleaning.Water break Test:Degree of degreasing is checked by pouring some water on the degreased surface if a continuous water film persists on the vertical surface of the article for 5 to 10 sec. Degreasing may taken as satisfactory.3.Grit Blasting : All surfaces will be shot blasted to Sa-2.5 as per IS 8504-4 After shot blasting , clean the component by air blast. Testing: (As per COR-W-01.)I.Visual testing: The shot-blasted surface shall be visually checked for proper cleaning to near white metal quality, and ensure that the surface

is free from any dust with the help of adhesive tape.II.Surface profile: Testex Press-O-Film: One section of the tape from the roll should be teared off.The adhesive tape on the back of the Press-O-Film should be removed.the press o film should be pressed over blasted surface. A blunt rounded stick/pencil or a similar rounded element should rub the film available at the center of the press o film. Until blasting profile is inscribed over the film. This will provide a reproducible surface profile.the thickness of inscribed film should be checked by Micrometer. The original thickness of the film i.e. 2 thou/ mils (50 microns) should be subtracted from the reading obtained from Micrometer. The resultant thickness will indicate surface profile parameter.The surface profile should be 60- 80 microns.Hot Zinc Spray Coating:Hot zinc spray galvanizing @ 100 microns minimum according to EN ISO 2063.The zinc spraying material is to be selected according to type Zn 99.99,

ISO 752/DIN 8566. Zinc Spray has to be applied around the flange on the outside and including the transition into the wall. Incase long term storage, mask off contact surfaces to protect them against oxidation.

Testing of coating:(As per COR-W-01.)

Visual Testing:Coated surface should be uniform, without any blisters & free from non adhering metal.

Adhesion Test: The coating shall satisfy the GRID test.

The coating is cut through the base metal to give the square lattice pattern having 15mm X 15mm dimensions.The distance between cuts is 3mm.After the lattice pattern a suitable adhesive tape shall be applied to this part by means of a roller with 500g. load.The adhesive tape shall be then pulled off in a quick and abrupt manner in a direction perpendicular to the surface.No part of the coating shall separate from the base metal.

Sealer Coat:

After Zinc mettalising the surface will be coated with Two component

Epoxy Polyamide Zinc Phosphate(Amercoat 182 ZP HB) coating by airless gun to give minimum 100 micron dry film thickness, immediately after component is cooled down

Intermediate Coat:

Two component Epoxy Polyamide Micaceous Iron Oxide (Amercoat 383 HS MIO) System shall be applied over the Sealer coat by airless gun achieve min. 100 micron dry film thickness after 4-18 hours of application of sealer coat.

Top Coat :

Two component Aliphatic Acrylic Polyurethane(Amercoat 4124) shall be applied over the Intermediate coat by spray gun to achieve min. 80 micron dry film thickness after 2-16 hours of intermediate coat. Application :

All the coatings are applied by airless spray gun. The gun will be held at 25 to 30 cms from the surface & a wet coat will be applied with 50 % overlap.

Drying : Each coat of paint shall be allowed to dry as per manufacturer specification.

Paint Testing:-(As per COR W-01)

Dry Film Thickness: Total dry film thickness of the paint system should be minimum 380 micron.

Adhesion test:Pull of type:(As per ASTM D 4541- 95)

Defelsko Positest portable adhesion tester is used to carried out this test.This test has to be carried out at least at two spots per component.A tolerance of max. of 10% is allowed over manufacturers data.

Pin hole test:

Low Voltage Spark Testing:(Wet Sponge Technique)

This technique is used for locating pin hole between the non conductive coating and conductive surface.Sponge socked with a wetting agent such as water is supplied with a low voltage 67.5.When the sponge is moved over a pin hole liquid flows to the substrate

and complete the electrical circuit.The resulting current flows generates an audible alarm in the detector.

Disposition Action:If pin hole is detected, the same has to repaired by applying subsequent coat of one or two locally after surface preparation through Emery paper 180. Then spark testing should be carried out locally to ensure pinhole is sealed.

Shade of coating:shade of top coat should be as per RAL shade card 7035

Yes

No

Drying for 2 hr.

Send for further operation

TestingOk?

Masking of machined surfaces

Testing Ok?

Shot blasting

Air blast cleaning

Zinc Metallising

Application of sealer coat of Amercoat 182 ZP HB

Testing

Ok?

Drying for 4 hr.

Testing

Ok?

Machining/forming

Testing

Ok?

Application of Top coat of Amercoat 4124

Drying for 2 hr.

Application of intermediate coat of Amercoat 383 HS MIO

Yes

Yes

Yes

Yes

No

No

No

No

Degreasing

Shot Blasting BoothA complete enclosure in which blasting operations are performed and where the operator works inside the room to operate the blasting nozzle and direct the flow of the abrasive material. The abrasive projection through compressed air has some dangers due to the high speed of the grains projected. The treatment operations have thus to be done in a closed enclosure in order to protect the environment.

Advantage:

1.Reduce the wastage of abrasive.

2.It ensures the treatment isolation, the recovery of dust and abrasives.

3.It protect the body injuries & eyes from hitting of abrasives.

4.It helps to maintains the environmental conditions.

Paint Booth

Paint booths are essential ingredient of paint application industries.

2. Paint booths are fire & health protection enclosures designed to maintain the environmental conditions & quality of painted component.

Advantages of spray booth

•1)     Safety

•2)     Quality of finish

•3)     Work environment.

For preparing proper Paint booth following points to be consider 1.1

)     Space available 2.2

)     Part dimensions 3.3

)     Application method 4.4

)     Production rates 5.5

)     Materials sprayed.

Space Available : 21m X 8m Part dimension :The job to be painted is circular shaped

having diameter 4m and 0.6m.height.Application method :Airless spray method.Production rate :3 nos. per dayPaint consumption :max.60 liter per dayMaterial sprayed :Following materials are sprayed in the

painting booth.Zinc metal wire (Zinc Metallising) Dft : 100 micron Epoxy high build Zinc phosphate primer. Dft : 100 micron Epoxy MIO based paint Dft : 100 micron Aliphatic acrylic/ PU paint. Dft : 80 micron

Top view

Front view

SPECIFICATION OF SHOT BLASTING & PAINTING BOOTH CLOSED ENCLOSURE:Material specification:Galvanized sheet - 1mm.thick. Column - 150 mm.Vertical members - 100 mmAngle horizontal - 50 mmCosting:Supply & fixing of corrugated sheets - Rs. 97,000 Supply & fixing of structure - Rs.4,08,000Total cost for fixing the enclosure - Rs.5,06,000

Dust extraction system(filter cartridge type) - Rs.6,00,000

Painting Extraction(paper filters/ non-woven fabric) - Rs.4,50,000

Mettalising Extraction(cyclone separator) - Rs.3.60,000

Miscellaneous Items: - Rs.1,27,000Tarpaulin covesRubber LiningFRL unitFlame proof lighting Fixtures And connections Civil work & Chequered plates - Rs. 1,13,000

Total Estimate for the shot blasting & paint booth - Rs. 21,56,000

Dust extraction system:Cartridge filter type Dust collector is provided to extract dust from the shot blasting and air wash separator system. It is fabricated out of 4mm/3mm plates suitably reinforced. Cartridges of non-woven cellulose/polyester are provided to filter the dust collector air. Cartridges divided the dust collector into two zones: -Dust laden or incoming zone, andClean air or exhaust zone.Dust laden air is sucked from the shot blast system and conveyed to the dust collector system through various ducting at conveying speeds of 2000 to 3800 m/min. As the dust-laden air enters in the dust collector, it expands due to increase in the cross section and is directed upwards towards the filter. The combined effect of expansion and change in the direction helps separation of larger particles of dust, which fall and get collected in the hopper provided below the dust collector. As the air passes through the filter particles up to 1 to 5 microns size get filtered.  

 The filtering, mainly due to the formation of thin layer of “Filtering Cake” which forms within few seconds and is primarily responsible for efficient filtration. The clean air passing through the filter is sucked by the exhaust blower and exhaled to the atmosphere. As the filtration takes place, the thickness of filtering cake keeps increasing. This increase in the thickness of the filtering cake offers higher and higher resistance to airflow and reduces the effectiveness of the extraction system. It is, therefore, necessary to remove this cake, which is achieved by reverse pulsejet. Strong jet air at a pressure of 6 to 7 kg. / cm2 is shot for a fraction of a sec. in the opposite direction of airflow through the filters. This action is sequentially carried out through all this filters. This knocks of the layer of dust deposited on the filter area. The loose dust falls off and is collected in the hopper. The cyclic action continues to clean the filters, a couple of them at a time. A simple water manometer is provided to indicate the pressure difference across the filter cartridge.

Current Process:1. Normally Conventional Gravity feed spray gun was used for

painting.2. Due to conventional spray gun, over spray, bounce back was more.3. It’s a time consuming process & transfer efficiency is less.4. Low film build, so required more coats to achieve the recommended

thickness.5. High air pollution due to high emission. Improved Process: Airless spray gun is used for the paint application. Airless spraying is a method of spray application that does not

directly use compressed air to atomize the coating material. Hydraulic pressure is used to atomize the fluid by pumping it at high

pressure through a small orifice spray nozzle tip located at the front of the airless gun.

The fluid is discharged at such a high velocity that it tears itself apart and sufficient momentum remains to carry the minute particles to the surface.

AIRLESS SPRAY GUN

Benefits: 1. It is the fastest method of spray atomization.

2. Improved transfer efficiency due to a reduction in fog and over spray.

3. The ability to spray into recesses and cavities with a minimum of material bounce-back, and reduced spray booth maintenance.

4. High film build so the required thickness can be achieved in one coat.