Major Purchasing Tasks

Make sure incoming materials and the actual raw material stock holding are of the smallest possible size, without affecting operational performance.
Adopt a ship to shopfloor strategy, in other words as soon as a part hits the goods inwards area and passes any inspection stage it is consumed on to the shopfloor as soon as possible.
The purchasing function would help establish the minimum and maximum stock holdings of any given parts.

Receive part Just-In-Time to be consumed.
Frequent deliveries to within a few hours of the production cycle.
Use a Kanban system to signal for more supplies.
Where parts of a Kanban nature ensure they are delivered direct to the shopfloor.
The purchasing function establishes the contracts to ensure delivery, performance and inspection data are adhered to.

Make sure the vendors inspect the parts fully and give appropriate conformance certification, it means your inspectors have less things to inspect.
Use the vendor conformance certification to give feedback to suppliers on the quality of service.
Make sure the vendors are responsible for providing corrective action reports.
It would be up to the purchasing function to monitor suppliers.

Reduce the number of suppliers.
Discuss future requirements on master production schedule with suppliers.
Introduce blanket orders based on leveled schedules for constant orders, the regular repeaters and the irregular order.
Target a reduction in the cost of any bought out items/services with suppliers.
Ensuring quality and delivery standards.
Integration with suppliers for placing commercial contracts.

Movement of material from supplier to the buyer premises.
The contract may be based on purchasing negotiating a call off contract where the supplier holds a certain amount of material in their stores based on a blanket order from the buyer who then calls off the amount of material as and when required.
Material movement can be based upon a Kanban, levelled schedules, etc.
Logistics need to co-operate with the purchasing section to establish the most suitable stock movement strategies.

Understand strengths and deficiencies of suppliers.
Establish common rules as a basis for discussion related to planning, control, attitude, handling, tooling, quality, etc.
Well trained purchasing employees would be used integrate the buyer-supplier relationships more closely.