Section 4. Construction of the Automotive Department Assembly Plant and Koromo Plant

Item 4. Description of the Koromo Plant

The plant layout drawings for the first phase of construction of the Koromo Plant, which was completed in November 1938, are as shown in Figure 2-1. The site area was approximately 500,000 square meters, and the building area was approximately 200,000 square meters. Total construction costs were 45 million yen.

As can be seen in Table 1-5, the Koromo Plant was an integrated production plant that included all processes necessary for automobile production including casting and forging blank processes, machining, mechanical assembly, stamping, body assembly, painting, and overall assembly. Each process was laid out so they were connected, and the Koromo Plant formed the basis of future plants.

Table 1-5. Facilities of the Koromo Plant (1938)

Category
Plant
Products
Dimensions
(shaku)
Area
(tsubo)
Area (m2)
Casting
Special casting plant
Cylinder blocks, cylinder heads
138×276
1,058
3,491
Ordinary casting plant
Transmission cases and other parts
78×501
1,085
3,582
Forgeable iron casting plant
Differential cases and other parts
90×501
1,252
4,133
Annealing plant
Forgeable iron cast product heat treatment
366×90
915
3,019
Coring plant
Various cores
138×150
575
1,897
Wooden mold plant
Wooden molds for cast parts
72×204
408
1,346
(No. 2 special casting plant)
(Cast crankshafts)
(108×300)
(900)
(2,970)
Machining
Tool and machine plant
Tools and machine tools
120×390
1,300
4,290
Forging
Forging plant
Rear axle shafts, knuckle arms, connecting rods, gears, and other parts
84×384
896
2,956
Tempering plant
Forged product heat treatment
96×144
384
1,267
Machinery
Machining Plant No. 1
Engine part machining
168×360
1,680
5,544
Assembly Plant No. 1
Engine assembly and testing
168×270
1,260
4,158
Machining Plant No. 2
Transmission and steering part machining
168×360
1,680
5,544
Assembly Plant No. 2
Transmission and steering assembly
168×270
1,260
4,158
Machining Plant No. 3
Suspension part machining
168×360
1,680
5,544
Assembly Plant No. 3
Suspension part assembly
168×270
1,260
4,158
Plating
Plating plant
Plating
96×180
480
1,584
Heat treatment
Quenching plant
Carburizing and carbo-nitriding, annealing
108×270
810
2,673
Stamping
Stamping plant
Stamped parts
120×570
1,900
6,270
Auto bodies
Autobody plant
Autobody plate processing and body assembly
240×720
4,800
15,840
Painting
Paint Shop No. 1
Frame and suspension part enameled baked on paint
42×450
525
1,732
Paint Shop No. 2
Small component lacquer application
66×450
825
2,725
Paint Shop No. 3
Body painting
90×450
1,125
3,712
Assembly
General assembly plant
Passenger car outfitting (second floor), truck chassis assembly and passenger car assembly (first floor)
120×450
1,500
4,950
×2
×2
×2
Inspection
Adjustment plant
Inspection of completed vehicles and chassis and adjustment
120×90
300
990
Repairs
Repair plant
Paint touch up
36×156
156
514
Note:
Parentheses indicate facilities constructed after 1938.

With regard to the continuity of the processes, various transport conveyors were installed in sand processing facilities and casting sand transport systems in the casting plant as well as the painting plant and the final assembly plant with the aim of flow production based on the Just-in-Time system (see Item 5.). Initially, a conveyor system was not installed in the machining shop, but overhead space was provided in the plant building and electric lines and steam and compressed air pipes were placed in underground pits or on poles to avoid interference with other facilities when a conveyor was later installed and secure the space needed for a conveyor.

In addition to these direct production facilities, the plant also included a test track, forging (blacksmithing) shop, maintenance shop, warehouses, a cafeteria, and more. The engineering divisions included the Administration Office (including the Engineering Officers Office), Design Office, Chemical Testing Office, Vehicle Testing Office, Aircraft Research Office, Photo Office (Drawing Office), and Prototype Office. In addition, the site also included a head office Administration Office, dorms, a school (to train technical workers), and other administrative and benefit-related facilities.

Kiichiro Toyoda made the following statement concerning the significance of the Koromo Plant:

Our mission is to make the car a more complete, more convenient, and more economical product. We have been investigating the question of whether there is a way to make these improvements as quickly as possible without any sacrifices for the past five years. It requires fundamental reforms in plant organization.
We made substantial efforts with the Kariya Plant, but we were unable to make the reforms that we intended. Toyoda did not start making automobiles with the expectations that it would be a major source of income from the beginning. There is no value in conducting a car business with the factory organizations that cannot make progress in reforms. We then moved to the Koromo Plant with completely new facilities and a new organization. If we extended the Kariya Plant, we could have used somewhere around 700,000 to 1,000,000 m2, but the major reforms that we were seeking would not have been achieved, so we decided to try building a completely new plant at Koromo despite the inconvenience. When Koromo Plant was completed, we established an organization that could quickly make improvements with a minimum of sacrifice.1

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