Shaped PCD Tool Components With Local Diamond Layering
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Solution Overview
Problem
The high cost and complexity of producing shaped tool inserts from polycrystalline diamond (PCD) limit their widespread use due to the material's propensity for fracture and chipping, especially in complex geometries, as it is less strong and tough than cemented carbide materials.
Innovation Solution
A method involving compacting diamond feedstock at 1300° C. to 1500° C. and 5 to 8 GPa pressure for 15 to 25 minutes, followed by sintering at 1400° C. to 2100° C. and 7 GPa pressure for at least 30 seconds to form a sintered PCD body, which is then shaped using EDM or laser cutting, allowing for a PCD table only where needed, reducing unnecessary material usage and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If superhard materials (PCD/PCBN) are used for machining hard workpiece materials, then cutting performance is improved, but toughness and resistance to fracture/chipping deteriorate
Solution Approach 1:
The invention uses a composite structure consisting of a superhard material layer (PCD or PCBN) bonded to a support substrate (typically cemented tungsten carbide). This composite structure allows the tool to exhibit both the hardness of the superhard material for cutting and the toughness of the cemented carbide substrate for resistance to fracture and chipping.
2Strength
If shaped tool inserts with complex geometries are produced from PCD, then cutting performance is improved, but production cost increases
Solution Approach 1:
The invention segments the tool insert into two distinct parts: a PCD cutting layer and a cemented carbide support substrate. This segmentation allows each material to be optimized for its specific function while being produced through separate processes, reducing the overall manufacturing cost compared to producing the entire insert from expensive PCD.
Solution Approach 2:
The invention applies PCD only where it is needed - in the cutting layer at the tool tip - while using less expensive cemented carbide for the support substrate. This local quality approach ensures that the expensive superhard material is used only in the region requiring maximum hardness, reducing overall production cost.
3Duration of action of stationary object
If PCD is used for tool inserts, then wear resistance is improved, but material cost and production complexity increase
Solution Approach 1:
The invention uses a preliminary bonding process where the PCD layer is bonded to the cemented carbide substrate before final shaping. This preliminary action creates a stable composite structure that can then be shaped more easily and economically, reducing overall production complexity while maintaining wear resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the economical production of shaped PCD tool components with heights of at least 10 mm, reducing waste and maintaining mechanical integrity by ensuring only the required thickness of PCD is used, thus addressing the cost and durability issues of traditional PCD tool production.
Implementation Method 1
Compacting diamond feed stock in a sufficient quantity to form a green body having a height of at least 10 mm post-compaction, compaction occurring at a temperature in the range of 1300° C. and 1500° C., at a pressure in the range of 5 to 8 GPa and a duration in the range of 15 to 25 minutes
Implementation Method 2
Sintering the green body at a temperature between 1400° C. and 2100° C. and at a pressure of at least 7 GPa, for at least 30 seconds to form a sintered PCD body
Data Source
AI summary
This disclosure relates to a method of making a polycrystalline diamond (PCD) body comprising a PCD table with a height of at least 10 mm.