Sharpening Radial Teeth on Disk Using Dry Milling
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Solution Overview
Problem
The existing methods for sharpening radially extending teeth on disks, such as those used in pulverizers and powder mills, are inefficient and costly due to the use of expensive grinding wheels and time-consuming processes, resulting in high costs and long lead times for sharpening.
Innovation Solution
A dry milling process using a cutting head with a rotary cutting element and a computer-controlled machine that moves the disk relative to the cutting head, allowing for precise sharpening of teeth without coolant and reducing the sharpening time to about 45-60 minutes with only one pass per tooth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional grinding process is used to sharpen teeth, then teeth can be sharpened, but the process is time-consuming (2-4 hours per disk) and expensive
Solution Approach 1:
The patent replaces the traditional grinding mechanical system with a high-speed electronic cutting system using carbide inserts that rotate at 10,000-20,000 RPM. This substitution eliminates the need for slow abrasive grinding and enables precise material removal through controlled cutting actions, reducing sharpening time from 2-4 hours to minutes while maintaining tooth geometry precision.
Solution Approach 2:
The invention changes critical process parameters including cutting speed (10,000-20,000 RPM vs traditional grinding speeds), cutting mechanism (intermittent cutting passes vs continuous grinding), and tool material (carbide inserts vs abrasive wheels). These parameter changes transform the sharpening process from a slow, expensive operation to a fast, cost-effective procedure that removes material more efficiently.
2Ease of manufacture
If traditional grinding process is used to sharpen teeth, then teeth can be sharpened, but the cost is high (about 10% of new disk cost each time)
Solution Approach 1:
The patent employs disposable or replaceable carbide cutting inserts that are significantly cheaper than traditional diamond or PCBN grinding wheels costing $1,800-3,000. These carbide inserts can be replaced when worn, eliminating the need for expensive grinding wheel purchases and reducing the overall sharpening cost from 10% of disk cost to a fraction of that amount.
Solution Approach 2:
By substituting the expensive grinding mechanical system with a high-speed cutting system using carbide inserts, the patent eliminates the need for costly grinding wheels and reduces machine operating costs. The new system requires less power, generates less waste, and completes the sharpening operation in a fraction of the time, dramatically reducing the cost per sharpening cycle.
3Manufacturing precision
If multiple passes of grinding wheel are used per tooth, then teeth can be completely sharpened, but the process becomes even more time-consuming
Solution Approach 1:
The patent uses periodic intermittent cutting passes with the carbide inserts, where the cutting tool engages and disengages the tooth in controlled cycles. This periodic action allows for precise material removal while enabling chip evacuation and cooling between passes, achieving complete tooth sharpening in fewer cycles compared to continuous grinding while maintaining precision.
Solution Approach 2:
The high-speed cutting system with carbide inserts removes material more efficiently than grinding, requiring fewer passes to achieve complete tooth sharpening. The precise cutting action and controlled feed rates enable the system to achieve the same level of tooth restoration in a fraction of the time required by traditional multi-pass grinding operations.
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
The dry milling process significantly reduces the sharpening time and cost, making the process more efficient and cost-effective compared to traditional grinding methods, while maintaining the disk's integrity by cutting away metal from the teeth.
Implementation Method 1
A dry milling operation to sharpen the teeth. Milling, as used in the machining arts, refers to removal of material with a cutting head, e.g., a rotating cutting head, having one or more cutting elements.
Data Source
AI summary
A method for sharpening radially extending teeth on a disk included: 1) sharpening a tooth by moving the disk relative to a cutting head, 2) separating the disk from the cutting head, 3) indexing the disk to the next tooth, 4) engaging the cutting head with the next tooth, and repeating steps 1)-4) until sharpening is complete. A machine for sharpening teeth includes: a table movable in the x-y plane, an angle plate mounted on the table for holding a disk, a digital indexer for rotating the disk, a cutting head for sharpening the teeth, and a computer for the controlling the movement of the disk relative to the cutting head by sequentially moving the disk via movement of the table and rotation of the disk on the angle plate. A rotary cutting head has a cutting element affixed at a periphery of the head.