Objective

One of the principal objectives of most manufacturing facilities is to improve the quality of MWF service.  Anyone who has had responsibility for MWF for any period of time, has recognized the need.  A simple spreadsheet can be used to schedule a sophisticated MWF management program.

Inspection Frequency

Each machine requires inspection by a trained individual, at intervals generally shorter in time than that of the Service Frequency.  Inspection incorporates the accumulation of both sensory observations and analytical measurements.  After making the scheduled observations and measurements, the MWF staff member will make the necessary adjustments to the controllable parameters such as the volume and concentration while at the machine.  If the inspection reveals the need for a change-out or recycle, the MWF staff member will adjust the scheduled Service Frequency for that machine.  The MWF staff member will also note other problems for engineering review, such as rust, paint removal, and requests for coolant modifications.

1. Sensory observations may include:

1. Tank condition: volume.

2. Tank condition: machined solids build-up.

3. Coolant condition: aromatic condition.

4. Coolant condition: contamination (oil and debris).

5. Coolant condition: foaming, color, uniformity.

6. Machine condition: rust, paint, sight glass.

2. Analytical measurements may include:

1. Concentration.

2. pH.

3. TDS (total dissolved solids).

4. Oil content.

5. Microbial growth.

Service Frequency

Each machine requires service by a trained individual, at a frequency in time specific to that machine/operation.  "Service" is intended to mean a complete "Change-out" or a "Recycling" of the coolant.  The Service Frequency is usually expressed as a number of weeks.  Ideally, the Service Frequency is an even multiple of the Inspection Frequency.  For example, if the Inspection Frequency is every week, the Service Frequency might be every 4 weeks, or every 6 weeks.

The Service Frequency for a machine with a high quality filtration unit running a synthetic coolant may be 6 months or more.  Other machines with water-soluble products and no filtration may require weekly service.

Change-out

A change-out is the most costly operation involving coolant maintenance of a machine.  Substantial labor and equipment is involved as well as a shutdown of the machine.  A change-out consists of:

1. Shutting machine down.

2. Machine draining.

3. Machine cleaning.

4. Machine re-filling.

5. Disposal of sludge/cuttings.

6. Transport of coolant to a recycling or disposal station.

7. Pumping coolant into and out of a tanker vehicle.

Recycling

Recycling is the obviously superior solution to change-outs with new coolant (use and dispose), and portable recycling is another magnitude superior to stationary recycling.  Stationary recycling requires all of the above listed steps for a change-out, the exclusive cost savings being the cost of new coolant and disposal costs.  Portable recycling requires none of the above listed steps/costs and still saves coolant and disposal costs.  Modern recycling equipment is capable of killing dangerous and harmful fungus and bacteria that simple decanting equipment cannot.  In addition, portable recycling allows for maintenance of numerous coolants, concentration, and provides specific identification of the product age.   When stationary recycling is combined with portable recycling, you get the longest possible life from the coolant, and the best economics, but you give-up traceability of the product (it is mixed with coolant from other machines).

Recycling Limit

Each machine has a portable recycling limit, or number of times the coolant can be recycled before a change-out, or temporary removal of fluid is necessary to clean the coolant tank.  This is the inherent limitation of portable recycling.   The sump must still be evacuated eventually to remove sludge.  Upcoming changes in technology will likely address this issue.  The recycling limit is thus controlled by variables effecting either the need to clean the sump, or the life of the coolant.  Examples are as follows:

1. Variables limiting tank performance:

1. Machines tank volume (smaller tank = lower limit).

2. Machining operation (grinding = lower limit).

3. Machine filtration systems (no filtration = lower limit).

2. Variables limiting coolant recyclability:

1. Coolant chemistry and quality.

2. Water quality.

3. Recycling equipment performance.

Unscheduled Service

Some or all of the coolant related machine servicing is normally unscheduled.  If none of the service is scheduled and the shop has more than 5 or 6 machines, money is being wasted.  The amount of money wasted is relative to the number of machines serviced.  The following is a partial list of cost associated with an unscheduled (reactive) service program:

1. Labor: Machinist time.  Reporting problems, operating with substandard coolant condition, set-ups, additional down-time for service.

2. Labor: MWF Staff.  Additional service events per year, inefficient service logistics between machines, additional waste shipments.

3. Material: Additional new coolant purchases, additional waste coolant disposals.

4. Other Costs: Inability to track coolant usage, inability to track machine problems, inability to objectively determine coolant performance, inability to prepare for work schedule changes (holidays and weekends), inability to maintain level manpower requirements, tooling costs, machine repair cost, workers compensation liability, dissatisfaction of workers with service, etc.

Scheduled Service

A scheduled service program is by far the most cost efficient and satisfactory program to the organization.

Cost of Service

The Cost of Service is the total of all costs associated with each event of a Service Frequency.  The failure to properly service machine coolant gives rise to a number of other costs. The primary elements of the cost of service include:

1. Inspection frequency.

2. Service frequency.

3. Recycle limit.

4. Tank capacity.

5. Coolant purchase cost.

6. Coolant disposal cost.

7. Inventory cost.

8. Labor (machinist).

9. Labor (MWF staff).

Distribution Problem Observations

The following observations are common:

1. Machine Filling.

Substantial time is spent filling machines with additional coolant to compensate for chip drag-out and evaporation.  To have a machine refilled, an operator must page a member of the MWF Staff, or do it himself, risking control of the concentration, mixed materials, and the numerous problems that these errors cause.

2. Drum Storage.

A quantity of drums must be stored around the shop to allow for convenience in refilling the machines.  Shop storage of drums is undesirable.  The drums take up valuable shop space, leak, are unsightly, and costly to maintain as an inventory when spread around the facility.

3. Machine Placement.

Machine placement is assumed permanent.

 

Coming soon!

A sample spreadsheet for MWF Maintenance that you can download.