Glazing stands as a pivotal stage in the sanitary ware manufacturing process, often integrated with the inspection phase. This combined step is referred to as “control & spray,” wherein greenware undergoes inspection before the glazing process commences. The focus of this article is to explore the various methods of glazing, particularly delving into manual, robot, and carousel glazing. Each of these methods carries its unique set of advantages and disadvantages. The ensuing discussion will involve a comprehensive comparison of the spraying processes associated with these three glazing methods, shedding light on their respective merits and demerits. Let’s embark on an examination of each method, evaluating their performance across different factors.

MANUAL SPRAYING:
In this process, dried greenware undergoes initial inspection in one booth before being manually transferred to another booth for the spraying phase. The sprayer in the second booth applies the coating and then manually moves the piece for logo stamping, which can take place either on a table or on an unloaded trolley. The transition between the two booths can be facilitated through manual handling, by using a trolley, or by employing a roller conveyor.

ROBOT SPRAYING:

A robotic system is employed for the application of glaze on dried greenware pieces. The process initiates with an inspector examining the dried greenware in a dedicated booth. Subsequently, the inspected piece is conveyed to the robot through a moving mono rail conveyor, belt conveyor, or a robot turntable. The robot executes the glazing based on a programmed number input by the operator, who may either be an inspector responsible for checking and loading the piece onto the table, or a loader tasked with bringing the piece from the inspector and loading it onto the turntable.

Once the robot completes the glazing process, the turntable moves the piece to the unloader. The unloading personnel then proceed to stamp the logo and unload the finished piece.

CAROUSEL SPRAYING:

A carousel is a conveyor system shaped in either a round or square configuration, comprising a long chain conveyor with attached turntables spaced at regular intervals. This carousel facilitates various tasks performed by different teams to process the pieces. The operational sequence within the carousel involves loading the dried green piece in one area, followed by movement to the polishing section for the application of polish. Subsequently, the piece advances to the inspector, who assesses its quality and categorizes it as either good, repairable, or defective.

Continuing through the carousel, the piece then reaches the spraying area, where three sprayers apply distinct coatings. Following this, a designated personnel stamps the logo on the piece, and finally, the unloader completes the process by unloading the finished piece. Notably, all these tasks are seamlessly executed within the carousel itself.

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Installation Cost:

Comparing the initial setup costs directly on a one-to-one basis is not straightforward, as the configuration of three manual booths and three inspection booths is equivalent to a single carousel. It’s worth noting that the setup cost of a manual booth is lower than that of a carousel, and the cost of a carousel is less than that of a single robot.

Production Rate (Pieces/Hours):

• Average Time required to spray a single WC on manual booth = 3 Mints
• Average Time required to spray a single WC on carousel = 20 Sec
• Average Time required to spray a single WC on robot = 2 Mints.

Of course, Manual booth we have two people and Carousel we have 15 people and Robot we have 3 people minimum. So we can’t use the above data for direct comparison. But as per my view carousel seems to be the winner in Production rate.

Maintenance Cost:

• Manual booth does not have anything other than the exhaust blower motor so the maintenance is minimum on the manual spray system.
• Carousels have Motor for running the carousel chain and gearbox. So the maintenance cost will be higher than the Manual spray booth.  But any kind of maintenance problem can be carried out by company engineering people. No need special engineering people from the manufacturer because the design is simple.
• Robots are full of electrical and mechanical parts.   Small problems like zero point missing and the spray gun issue can be solved easily. But major problem means required special professional from manufacturing company to solve the issue. Maintenance cost is comparatively high compared to other two methods of spraying.

Breakdowns:

• In the case of manual booths, they can be deemed to have virtually zero breakdown time. Even if the blower is not functioning, spraying can still be carried out.
• Carousels, on the other hand, entail a minimum break time of 1 hour per week. This break time may extend as the carousel chain ages, and potential breakdowns may occur due to issues with the chain or motor. However, aside from these concerns, there are generally no other notable issues with carousels.
• Robots, in comparison, pose more challenges. Identifying the issue alone can sometimes take an entire day, making them potentially more time-consuming and complex in terms of troubleshooting and maintenance.

Quality of Spraying (Efficiency /Yield):

We are now analyzing, which method of spraying can make the problem.

• In a manual booth, the probability of errors is considerably high since the entire process relies on manual handling.
• While robots generally operate smoothly, occasional issues like a clogged gun may arise, leading to potential defects in under-glazed products. Additionally, problems related to the robot’s zero point missing may occur, contributing to potential issues.
• In a carousel setup, where three individuals each provide one coating to the same product, the likelihood of mistakes is significantly reduced. Furthermore, the errors made by one person can be compensated for by the other team members, enhancing overall quality control.

Manpower Requirement & Production Capacity:

• In manual spraying normally we required 3 people. One is inspector and other is sprayer and other is logo stamper. The production capacity of a set of inspection and spray booth per 8 hours is around 180 WC.
• A single carousel requires a minimum of 13 people.  Loader, polisher,  air blower, inspector, sprayer, logo stamper & unloader.  A single carousel can produce up to 900 Pcs of Water closets in 8 hours.
• A robot requires three people for operation. Three people are inspector, operator and unloader.  A single robot can produce a maximum of 200 Pcs per 8 hours. This calculation is based on no-break and offline spray program.

Labour Skill Requirement:

• The manual booth sprayer requires much more skill than the carousel sprayer.
• The operator or unloader does not need much skill for operating but a skilled technician required to make the program for the robot to spray for a particular design.
• Carousel needs only average skilled sprayed to operate. Because the sprayer needs to give only one coating for the ware.

Other Points:

Spraying a new model in robots takes time to create a program and robot can’t able to spray inside the bowl area so manual trap glaze needs to do before loading into the robot.

Conclusion:

We can’t come up with one best method for Control & spraying section because every method has its own pros and cons. But as per the point has seen above and with my experience, the carousel has more advantage than disadvantages.

I will try to add more points to this article based on your comment below. So comment and ask your questions.