Production line

In 1996, TMV put into operation the Welding shop together with the Painting shop, Assembly shop and Inspection shop for producing the first Toyota Hiace in Vietnam. After, to expand production of other car series, in 1997, two new assembly lines were installed in the Welding shop including W1 line (for Hiace) and W2 line (for Corolla, Camry, Land Cruiser, Vios and Zace).

Currently, W1 line is used for welding of passenger cars: Camry, Corolla, Vios with tact time is 12 minutes/vehicle. Innova and Fortuner Currently, the W1 line is used for welding of passenger cars: Camry, Corolla, Vios with the tact time of 12 minutes/vehicle. Innova and Fortuner are soldered on the W2 line with the tact time of 14 minutes/vehicle. After completing all welding processes on W1 & W2 line, the car will be transferred to the general line called SBL with the tact time of 6.5 minutes/vehicle.

The order in the Welding shop is as followed:

  1. Under rear process

  2. Side member process

  3. Main body process

  4. Fitting process

  5. Touch up process

Main bodies, side members and under rears are the localizable parts that are pressed in TMV’s plant. The other small parts are imported. They were put into the jig and soldered to be a main body using the point welding method in which workers use a welding gun that has two electrodes to create a high-intensity current to weld the  parts together.

With hundreds of welding points along the main body, in order to improve the accuracy of these, we have implemented many useful kaizens such as:

  1. Building a new system of Gun Guide: Gun Guide will be put into the jig directly to prevent workers from missing the welding points and its position.

  2. A system controlling the flaking of solders: There are too many welding points for workers to check the accuracy of them all. Therefore, the welding points will be divided sequentially for 5 consecutive vehicles. If all is good, the five cars will be transferred to the next step. If not, all of them have to be rechecked. By implementing this system, both the manufacturing time and the accuracy of the welding points are guaranteed.

  3. Memory balls on the welding gun: To maintain the accuracy of the welding points, the workers have to put 2 peaks of the gun at 90 degrees. If not, it may cause fire or perforation of the solders. After using the memory balls, the welding guns can’t be operated if they are not placed in the right angle position.

  4. Jig accuracy: This system ensures the high precision of welding fixtures.

Especially, with the purpose of “Heijunka” in production (otherwise known as  standardizing the production plan, in which the total number of vehicles to be produced (this number is determine once a month), engineers and Kaizen team have researched and manufactured one more main body jig called MBA2. Therefore, the parts of other models could be put into the MBA2 on standby after finishing MBA1 without waiting for MBA1 to be done to replace the jig and assemble parts of the next vehicles into this. So since May 2013, instead of using the “lot 5x5” method, the Welding shop has been converted its production method to Heijunka plan successfully.