Simplifying line design
Jan. 31, 2012
by Jim Stahlman, senior packaging manager, POWER Engineers
All production line design involves tradeoffs and compromises. Very often, production lines are designed and laid out in a plant based on short-term considerations: What seems easiest or is the least expensive from an equipment perspective? However, in order to achieve real cost efficiencies, the design basis for a production line should start with the consideration of material and personnel flow, as well as ergonomics. Money saved purchasing fewer conveyors will often be lost quickly with additional personnel costs and lost production time.
Begin the design with an overall drawing of the facility and mark flow information for the following on it:
- Where are the line consumables stored?
- Where will the finished products be stored?
- Where do the operators enter the area?
- Where are the fork trucks staged?
An ideal line layout will make the travel distances for consumables and finished products as short as possible. Map out fork truck travel lanes into and out of the area then look at the operator travel paths. To minimize safety issues and increase productivity, avoid having operator travel paths in the same area as the fork truck travel paths whenever possible.
CONSIDERING MATERIAL FLOWS.
It’s at this point that the line design can be based on the best material and personnel flows. Start the design with a block flow diagram of the system. Be sure the block flow includes the following:
- Consumables used by each unit operation
- Format the consumables will be delivered and how often they will need to be delivered (don’t forget about little things like glue and ink)
- Fork truck symbol or cart symbol when these are required to deliver the consumable
- Collection and removal of scrap materials on the line if this applicable
- A symbol for an operator if the unit operation requires a full-time operator
- Machine operational requirements between unit operations (for example, if a unit operation requires the machine to clear before a controlled shutdown show number of products required to clear the machine).
TIPS FOR EASIER ACCESS.
Next, use the information on the block flow to develop the actual line layout. Get machine templates of each unit and mark the operator and consumables access for each one. Arrange the machines based on the block flow diagram. Try to pair operator access points for machines to reduce operator travel. Be sure consumables and scrap access points for each machine are on an access aisle. Pay attention to the conveyors between each operation to be sure there is sufficient accumulation for controlling the machines.
Remember to work in three dimensions. Overhead conveyors can pose maintenance issues, but they can also free up access space for consumables and operators. If conveyors are included, proper conveyor design considerations can reduce related maintenance and cleaning issues.
One example of using elevation to help operator access is shown in the included drawing. Placing unit operations between conveyor lines requires walkover platforms for personnel access and special handling devices for consumables. Simply inclining some conveyors and proper design of the system allows for easy access around all of the unit operations.
The bottom line is that defining and listing all of the parameters and thinking outside the box can help with simplifying the operations of the line.
This story is sponsored by POWER Engineers, which has one of the most comprehensive teams of engineers and specialists serving the baking and snack industry. As an extension of its clients' engineering teams, the company provides program management, integrated solutions and full facility design for the baking and snack industry. Learn more at www.powereng.com/food.