User talk:SudhamsuKrishna


 * SEALER*


 * types & composition**

-Low Mastic Sealer and Mid Mastic Sealer are used as fillers between impact bars of the doors, and roof reinforcements, and the outer panels. These sealers remain spongy after setting. The applicaiton of these sealers can achieve waterproofing, rustproofing, dustproofing, and vibrational resistance.

--Composition Major components are: Styrene butadiene rubber Calcium carbonate Carbon black Calcium oxide Dicyandiamide (DCDA) Poly vinyl chloride (PVC) Di iso nonyl phphalate (DINP)

Both the mastic sealers have the same components but with different ratios.

--Physical Properties Sky blue colour, odourless, Specific gravity 1.450, Viscosity 210-290 million PS (at 20degC)[low mastic]/7-11 million PS (at 20degC)[mid mastic]

-Spot Sealer is used over spot welds to protect the weld are from corrosion. The sealer also provides water resistance, dust resistance, and vibrational resistance.

--Composition Major components are: Styrene butadiene rubber Calcium carbonate Carbon black Calcium oxide Dicyandiamide (DCDA) Poly vinyl chloride (PVC) Di iso nonyl phphalate (DINP)

--Physical Properties Black colour, odourless, Specific gravity 1.450, Viscosity 2100 +- 300 PS (at 20degC)

-Hemming Sealer is used at the edges if the sheet metal where hemming is done, like the edges of doors. Hemming sealer provides strength, and reduces vibration.

--Composition Major components are: Epichlorohydrin bisphenol A Calcium carbonate Carbon black Calcium oxide Glass

--Physical Properties Black colour, odourless, Specific gravity 1.500 +- 0.1, Viscosity 400,000 - 900,000 CPS (at 20degC)

-Body Panel Reinforcement (BPR) Sealer is used, as the name suggests, to strengthen the body panels. In addition to this, the sealer reduces vibration.

--Composition Major components are: Epichlorohydrin bisphenol A Calcium carbonate Carbon black Calcium oxide

--Physical Properties Black colour, odourless, Specific gravity 1.430 or less, Viscosity 150,000 - 250,000 CPS (at 20degC)


 * Problem Statement*

The sealer application system consists of the robotic arm and the sealer material pump. The robotic arm is responsible for the positioning of the nozzle, and the pump is responsible for the release of sealer material at pre-programmed locations. To apply sealer at a location, the robotic arm first takes the nozzle to that location, at which point the pump receives orders to release certain amount of sealer material. After this, the robot arm receives orders to proceed to the next location. The problem faced in this process is that sometimes the sealer material is not being pumped out of the nozzle. But robot arm anyway receives orders to move on to the next location. Hence, once in a while the sealer application doesn't take place. This is a concern as this might lead to customer dissatisfaction with the product. The aim of this project is to suggest a foolproofing system which can successfully detect whether the sealer has been applied or not at each location.


 * Current Foolproofing Method*

Laser sensors were installed at the stations to detect changes on surface of the sheet metal when the sealer material is applied. This method relies on the change in distance of the surface of the object on which the laser is beamed. Since sealer is a semi-solid substance, it slowly deforms on the surface and spreads to the sides marginally. This results in a continuous change in the heigth of the surface that the laser sensor is suppoed to detect. Hence, the sensor is not able to decide whether the sealer has been applied or not, and flags up a warning even when the sealer is applied. For this reason, this system has been bypassed. Manual checks are done to detect any errors in the sealer application. Mirrors at the next station provide a view of the location of the sealers. If a location is missed, then sealer is applied there manually. This method relies on humans, hence there is still a possibility of error. A more accurate system is required.


 * Suggestions For New Foolproofing System*

-Colour Image Sensor This sensor is very much like a camera. It takes the light from its view and depicts each pixel with the wavelength of the colour it detects. An image processing software can be employed to detect the application of sealer.

--Method of working: ---As soon as a workpiece arrives at the station, the sensor will take an image, and keep it for reference. ---After application of sealer, another image is taken. ---These two images will be compared for changes. ---As the model of the car is known, the image processing software can be pre-programmed with the locations where the sealers are supposed to be applied. The software can focus on these locations to detect changes. ---If no substantial change is detected then the software will raise a flag to notify the error in sealer application.

-Proximity Sensor A proximity detects pretty much anything that is kept in front it within its range. It works on the principle of magnetic fields. Any distortion in its field will be detected as the presence of an object in front of it. A proxity sensor can be mounted alongside each nozzle to detect sealet material flow from the nozzle.

--Method of working: ---The sensor system can be programmed with the locations where the sealer is to be applied. ---At each location of sealer application, the proximity sensor will detect sealer material flowing from the nozzle. ---When, at some location, the sensor doesn't detect any sealer release, the sensor system will raise a flag to report the error in sealer application.

Sudhamsu Krishna 05:06, 27 June 2012 (UTC)