Vision / Values

Meeting a Measurable Standard of Machined Parts Cleanliness

 

J. Byron Walker, Certified Manufacturing Engineer

Director

TECH TRANS UNLIMITED CORPORATION

Troy, Michigan // Los Angeles, California

 

 

By establishing consistent and repeatable manufacturing standards, and improving component specifications, manufacturers optimize quality throughout the expanding world market.

This approach allows a manufacturer considerable capability in terms of reduced capital expenditures and improved product to market timing.  The key assumption is that components are in compliance with accurate, measurable manufacturing standards.   

Clean Specs – the Traditional Way

Component cleanliness is a critical element of measurable manufacturing standards. To achieve these “clean-specs” standards, manufacturers have employed traditional cleaning/washing technology which has remained essentially unchanged for over three decades.

With the traditional machined parts cleaning process, debris entering the sub-assembly during the critical and capital intensive assembly process can cause a malfunction in the final assembly -- recognized only after the entire transmission, engine or other critical assembly has been fully assembled and failed during test or when in the hands of the customer.

A key limitation of traditional part cleaning is that the process does not include a verifiable and quantifiable methodology which can be repeated for every part to be within conformance of the standard.  Traditional washers fall short of achieving this goal for the following reasons: 

Design for failure

Without proper maintenance, filters eventually allow recirculated debris to plug the orifices of the spray nozzles.  Typical pumps require seals which become worn with the abrasive materials and pressures exhibited during initial installation.    Sludge and other deposits also build up within the washer booths which eventually damage moving conveyor components and guides.

Cost of operation

Traditional cleaning necessitates higher horsepower, increased heat, and longer cycle time to extract debris. Waste water pre-treatment and heavy contamination disposal also add to the manufacturing waste stream requiring additional cost for handling and disposal.

Repeatable Quality

Regardless of part orientation or directional orientation of fluid deliveries, internal cavities and dead-end tapped holes cannot be addressed by these systems.  This usually results in the attempted removal of chips and other extraneous debris via high air pressure utilization at considerable expense, or by being removed at the end of the line manually with compressed air or by other means.  Debris carried within the part can lead to contamination of critical components and failures requiring re-work and lost production during the manufacturing process.

Looking for a Better Way

Several major North American automotive companies recently drove the request to develop a repeatable and verifiable cleaning process that addresses the limitations noted above.   The scope of an advanced cleaning process required compliance within several categories:

  1. Fluid/flows deliveries and recoveries had to be monitored for deviation while being controlled over the course of the systems operation.
  2. All materials had to be structured for regenerative use to minimize energy costs and to improve reliability.
  3. The process had to incorporate a shortened process cycle time.
  4. The operational station and tooling footprint had to be no larger than the part of station addressing the part.
  5. Even with tool changes, the process could be applied to different parts.
  6. Instead of washing the outside of parts, this process had to clean the inside areas of a part including tapped holes, oil galleys, water jackets, etc.
  7. For assembly work between operations, the improved had to be within the allowable decibels for plant operation (80 d.b.a.) or less.
  8. Filtration and air purification had to be automatic and self-monitoring, requiring no scheduled maintenance.

Innovations in Parts Cleaning by “encapsulation and “surge” vacuum recovery:
A process known as “PULSED-CLEANING” ( Patented) has been incorporated within TTUC  supplied systems as well as licensed for use to U.S and Canadian Corporations., Inc.) to meet specific industry requirements and objectives as outlined above.

The in-line cleaning technology is a self-contained, proven process to effectively remove chips and debris from interior cavities of component parts either within the machining process or in-line during final assembly.A controlled vacuum, fluid and air mixture is accurately applied to recover debris such as machined chips from intricate interiors of complex parts and major surface areas.

"PULSED-CLEANING" delivers the following benefits:

Faster cycle times, cleaner parts:A high flow rate of fluid at lower pressures extracts chips from dead-end tapped bolt holes, and the fluids are recirculated and filtered so pump life is considerably extended.  The quantity of fluid required to perform the process is less than traditional washer systems due to the recirculation process capabilities.  The introduction of higher volumes of fluids leads to faster cycle times and cleaner parts.

High vacuum recovery and transfer:  The recovery of the expended fluids is performed using a high volume vacuum source.  This allows for high vacuum recovery rates and control of the debris and contamination extracted from the part before the fluid is re-introduced as a filtered media to the low pressure diaphragm transfer pumps. Debris is immediately removed from the surface of the part and not reintroduced elsewhere. Fluids introduced to the part are constantly recovered so the drying time and or next process cycle can occur more efficiently.

Regenerated energy: Directed air flows from the turbine/vacuum generator are engaged where appropriate and can be used for enhanced air flow and directional capabilities for improved parts drying within the short cycle required.

Improved design flexibility: The split half or “clam-shell” configuration allows consistent placement of fluid/air flow delivery and structured vacuum port recesses for efficient recovery.  In addition to these features, the noise levels are totally contained within the closed assembly.  Due to the high vacuum recovery capabilities, the main system vacuum generator and fluid separation capabilities can be mounted up to 100 feet or more, away from the station of operation.

Standardization: With the innovative cleaning process, the main vacuum generator station and fluid recovery towers are virtually duplicated for a wide spectrum of applications.  Selective alterations include the control of the turbine speed, air flows, vacuum force, cubic feet of air per minute, and controlled operational sequences.  One generic system design can be applied toward a large number of different products within this development by this flexibility.  Each station can be customized to meet the cleaning target requirements of any specific part.

Faster cycle times: The appropriate cycle time can differ somewhat between parts as alternate cycles on a large diesel engine compared to a smaller transmission valve body.  Normal cycle times for sub assembly cleaning between stations are 4-5 seconds generating a cleaned part every 11-12 seconds from one station.  Larger engines could require 12- 16 seconds depending on the quantity of tapped holes, water jacket access and other design criteria.

Improved Cleaning for Improved Quality: All in all, by implementing this process, manufacturers achieve a consistent, achievable standard of performance for parts or sub-assemblies regardless of where they are manufactured. 

Component cleanliness is a critical element of measurable manufacturing standards, and manufacturers may be assured that the parts being delivered for final assembly are usable and capable of providing fewer rejects during subsequent assembly operations. 

Finally, and most importantly, manufacturers can now achieve an improved level of quality leading to fewer warranty issues as well as enhanced customer loyalty.

 

 

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