The Seven Requirements For Optimized Machining Dennis Noland

The Seven Requirements: 1. Quality Tooling 2. Proper Machine Condition 3. Simplicity of Operation 4. Rigidity 5. Proper Speed to Feed Relationship 6. Proper Cutting Fluid 7. Operator Training

Each One of These Requirements Is Necessary For The Success Of Any Optimized Matching Application Today's demand for quality products, at a lower cost, has required all of us to look more closely at our manufacturing operations. The need to optimize our manufacturing process is not just a desire, but a true requirement for our futures. Optimized Machining is not achieved by following a set of fixed parameters, but by utilizing a sequence of conditions. These conditions are termed The Seven Requirements For Optimized Machining. All seven are required to achieve and maintain Optimized Matching conditions. They can also be used to evaluate our current operations, and to review Optimized operations to insure continual success.

Requirement (1) Quality Tooling

Quality Tooling Is A Necessary Requirement To Achieve And Maintain Optimized Machining Conditions.

Definition For A Quality Tool:

1. Reasonably Priced. (the most expensive is not necessarily the highest quality)

2. Product Consistency. (optimized machining requires a consistent tool)

3. Product Service. (the best tool in the world is not worth anything if the manufacturer can't support you)

4. Specially Designed Tooling. (utilizing special tooling, designed to fit the application, can yield a multiple increase in productivity levels and a lower cost per part)

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Requirement (2) Proper Machine Condition

Proper Machine Maintenance, And Matching Machine Capabilities To The Operation, Are Required For The Success Of Any Machining Operation

Proper Machine Condition List:

1.) Maintain machine to original operating specifications. (determine machines capabilities)

a. Set up maintenance program and maintain on a regular basis.

b. If it breaks, fix it the right way, the first time.

c. Better yet, fix it before it breaks.

2. Match machine to operational requirements. (utilize the machine's best characteristics)

a. Rigid machines should be used for the heavy machining operations.

b. Fast machines should be used for light matching of multiple operations.

c. Make sure machine has the physical capabilities for the job. (i.e. HP)

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Requirement (3) Simplicity of Operation

There is No Substitute For Simplicity, Complexity Adds Difficulty To Optimization

Simplicity List:

1.) Simplify setup for operation. (optimized machining includes setup time)

a. Standardize setup or setup procedures.

b. Make sure setup meets operational requirements. (i.e. rigidity)

2. Use common sense and simplicity to organize the sequence of operations. (create better flow)

a. Don't chase your tail around the shop.

b. Product consistency can be maintained better with simplified operations.

c. Break up multiple operations if necessary. (may also improve through-put)

3. Don't sacrifice any of the Seven Requirements. (you will lose more than you gain)

a. Use them as a guide to simplicity.

b. If one of them is lacking, it is costing you money.

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Requirement (4) Rigidity

Tool Life, Cycle Times, And Product Through-Put Can Not Be Optimized Without Rigidity

Rigidity List:

1. Machine rigidity. (must evaluate capability)

a. Make sure the machine has the proper rigidity for the operation.

b. Anti-backlash required on axis feeds for climb machining. (best tool life)

2. Part piece and setup rigidity. (evaluate best configuration)

a. Evaluate part configuration and machining orientation.

b. Design setup for maximum rigidity. (reduce number of operations if necessary)

3. Tooling system rigidity. (evaluate for maximum rigidity)

a. Use the largest diameter and the shortest length of tool possible.

b. Use a tool holding system designed for rigidity and the shortest overhang allowed.

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Requirement (5) Proper Speed To Feed Relationship

Metal Removal Rates Can Not Be Optimized If The Proper Speed To Feed Relationship Is Not Achieved

Proper Speed To Feed Relationship Requirements:

1. Relationship too far apart (poor tool life)

a. Speed too high and feed too low causes high frictional heat and rapid edge wear.

b. Adjust by bringing speed down first, increasing feed may cause tool to break if speed is too high and out of proportion for application.

2. Relationship too close together (catastrophic failure)

a. Feed too heavy for tool structure and causes tool to shatter, possibly damaging part piece and tool holding system.

b. Adjust by bringing feed down first, in case speed is also too high.

3. Determining proper relationship (work with application)

a. Start with a moderate speed for given application. (can not work with relationship if speed too high on first pass)

b. Start with medium feed and work up until machining conditions indicate relationship getting too close together (chattering), then back off 10% to 20% on feed. (this established optimum feed)

c. Increase speed and feed proportionately upward 10% to 20% at a time, until machining conditions indicate you have reached the upper limit for the application. (chattering, poor part finish, excessive vibrations)

d. Reduce speed and feed proportionately downward by 20%. (established optimized machining rates with safety factor)

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Requirement (6) Proper Cutting Fluid

Improper Cutting Fluid Or An Inadequate Amount Of Cutting Fluid Can Cause Premature Tool Failure

Proper Cutting Fluid Selection:

1. Running dry. (very poor tool life)

a. Don't ever run dry, unless you have to for safety's sake.

b. If you must run dry, keep speed on the low side (but not too low) and feed on the high side. (keeps frictional heat low and maintains heat in chip formation)

2. Water based coolant (for heat generating applications, water absorbs heat better than oil)

a. Use in applications, such as with finishing end mills, where light chip loads are common. (light feeds transfer more heat into the cutting tool)

b. Flood systems are much more efficient than mist. (mist systems must be positioned precisely to work properly)

3. Oil based coolant. (for heavy feed applications, oil does not absorb heat very well)

a. Use in heavy feed applications, such as with roughing end mills, where high chip loads are common. (thicker chips absorb heat better but need more lubricant to produce

b. Chilled high pressure systems work better than flood. (only if machine is enclosed, with mist extraction system)

4. Natural vegetable oil lubricant. (for heavy feed applications only, not a coolant)

a. Can be used as a replacement for oil based coolant applications. (it typically has a lubricity level 3 times that of oil based coolant, and is biodegradable)

b. Mist system is all that is typically required. (very expensive otherwise)

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Requirement (7) Operator Training

Operator Training Is Essential in Achieving And Maintaining Optimized Machine Applications

Operator Training Areas:

1. The operator must be a direct part of the optimization attempt for it to succeed. (he or she is the one who has to maintain it from now on)

a. Draw on the operator's experience. (no one knows their machine better)

b. Take the operator's advice on machine capability and required machine maintenance requirements. (will help you a lot in the early stages)

c. If they own it, they will take care of it. (you'll know they'll keep it going when you're not around)

2. The operator must know the differences between what they have been doing for years, and an optimized application, and how it reacts to changes. (machining conditions at elevated speeds and feeds react differently than those at lower speed and feed ranges)

a. They must clearly know how the operation functions and reacts. (sound and feel)

b. They must also know how to adjust the application properly, if something changes (nothing is ever 100% absolutely the same)

3. You must also train them, and yourself, to work together to achieve this common goal. (if you can not work together and trust each other, the operation will definitely fail, and everyone loses)

a. To error is human, grow from your mistakes.

b. Not to train properly, or in some cases not to train at all, would be inauspicious.

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