门排间距300mm与400mm的成本区别：
Cost difference between door row spacing of 300mm and 400mm:
以10米伸缩门（不含驱动部分）为例：
Take the 10m expansion door (excluding the driving part) as an example:
间距为300mm的伸缩门保定平面设计培训 收费岛模具 挡土墙模具 防撞墙模具 防撞墙模具 防撞护栏模具 大棚遮阳网 遮阴网，经计算需要制作34跨主框，
For the expansion door with a spacing of 300 mm, 34 span main frame needs to be made after calculation,
间距为400mm的伸缩门，只需要制作25跨主框就够了。
For the expansion door with a spacing of 400mm, only 25 span main frame is needed.
34跨主框按400mm的间距生产，可以制作13.6m门排
34 span main frame is produced at 400mm spacing, and 13.6m gate row can be made
25跨主框按300mm的间距生产，只可以制作7.5m门排
The 25 span main frame is manufactured with a spacing of 300 mm, and only 7.5 m gate row can be manufactured