Manual Vs Carousel Spraying Vs Robot Glazing for Sanitaryware Industry


Glazing is an important step in sanitary ware manufacturing process. Normally inspection and glazing done is the same step. A greenware will be inspected and then glazed so the department is called as control & spray. In this article, we are going to discuss the different methods of glazing options. I have worked with manual, robot and carousel glazing method. These three types of glazing have their own advantages and disadvantages. In this article, I am going to compare their three methods of spraying process to understand the merits and demerits of their own. First, we will see the process methods one by one and compare them with different factors.

In this method first dried greenware will be inspected in a booth and then passed to another booth by manually for spraying.Sprayer in another booth sprays the piece and move it manually for logo stamping. Logo stamping may be done on the table or in the unloaded trolley. The movement from the one booth to another booth can be done manually or by a trolley or using a roller conveyor.

The robot is used to spray the dried greenware pieces. Initially,y the dried greenware will be inspected by the inspector in a booth. The inspected piece will be sent to the Robot by a moving mono Rail conveyer or belt conveyor or robot turntable. The robot will glaze the piece based on the program number feed by the operator. The operator may be an inspector who checks the piece and loads it on the table or a loader just brings the piece from the inspector and load it on the turntable. Once the piece sprayed by the robot, then the turntable moves the piece to the unloader. The unloading person will stamp the logo and unload it.


Carousel is a round or square shape long Chain conveyer. Turntables are attached to the chain conveyor at a regular distance in between. In a carousel, the different set of people do different jobs to process the piece. First, the dried green piece is loaded in the one area of the carousel, the piece moves to the polisher area where the piece gets polished and then the piece moves to the inspector, the inspector will check the piece and mark as good, repair or bad. The piece moves to the spraying area where three sprayers will be giving three coating to the pieces. Then a logo person will stamp the logo on the piece. And the unloader will unload the piece. All the work will be completed in the carousel itself.

Installation Cost:

The initial cost or setup cost can’t be compared directly with one to one because 3 manual booth and three inspection booth is equalled to a single carousel. Of course, the cost of a manual booth setup is less than the carousel and the carousel cost is less than 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.


  • We can consider manual booths have zero breakdown time.  Even the blower not working we can spray actually.
  • The carousel will have break time minimum 1 Hour a week. When the chain of the carousel gets old the break time will increase. The carousel may break down due to Chain or motor issue. I don’t see any other issue on the carousel.
  • Robots will be a headache on this. Some time to pinpoint the issue itself will take a day.

Quality of Spraying (Efficiency /Yield):

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

  •  The chances of mistake in the manual booth are very high because the process fully depends upon the manual process.
  • Normally the robot will not give any issue, but there will be the time where the gun is clogged because of that many under glazed product can come.  And sometimes because of robot position missing there may be also we may find some problem.
  • In carousel normally three people spray the same product, each one of them gives one coating each. The possibility of mistakes is very less. And the mistakes of a single person can be covered by others.

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.


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.


  1. thank’s your informations help me so much in my work

  2. Nice study Mr.Venkat, a person who is new to this field will be easy to understand.


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