This article was originally published in the May 2025 issue of MFN – Metal Finishing News, as part of the “Good Vibrations” feature series. We’re proud to share it here as part of our ongoing commitment to improving finishing department efficiency and modernizing post-processing across traditional and additive manufacturing.
I. Introduction
This is the first in a series of articles I’ll be contributing to MFN Magazine throughout the year. My approach is to deliver high-impact insights in a short amount of reading time. I welcome your feedback—please reach out to MFN or to me directly with your thoughts. Your input will help shape future articles.
Across both traditional and additive manufacturing, many manufacturers face persistent challenges at the back end of production—especially in finishing and post-processing. Despite rapid advances in machining and 3D printing, the finishing department remains a bottleneck due to outdated processes and a shortage of skilled labor.
Is it time to update your mass finishing operations?
The Old and the New: Introduction of multiple newer finishing technologies to improve results and efficiency
During many visits to manufacturing facilities, I often ask:
- Why are you doing it that way?
- Most respond: “Because that’s how we’ve always done it.”
- Why are you asking us about the process now?
- “Because the person who always did it is no longer here.”
- May I speak to the Finishing Engineer?
- “We never had one.”
Let’s move beyond this. The following is a toolbox to help inform your decisions and approach.
II. Definitions
Below is a glossary of common mass finishing terms:
| Term | Definition |
|---|---|
| Hand Finishing | Manual force applied by one person to a single workpiece using handheld tools. |
| Mass Finishing | Automated process using media to finish multiple parts simultaneously in a particular style machine. |
| Tumbling | A general term, originally describing barrel finishing—the earliest form of mass finishing, but frequently used to describe other operations as deburring, wet grinding, wet cutting, vibing, burnishing, polishing, etc. |
| Vibing (Vibratory Finishing) | A method using a driven shaft with offset counterweights to create motion in a bowl or tub-style machine. |
| Stones / Media | “Stones” is outdated; “media” is the preferred term for abrasive or polishing materials. |
| Soap/Compound | A liquid or powdered compound used to enhance machine performance, tailored to material and process. |
| Polishing | Often refers to manual processes like belt sanding, buffing, or grinding to remove burrs or produce a desired surface finish. |
| Shiny | A subjective description of light reflecting, surface appearance with no standardized measurement. |
| Surface Ra | A measurable surface roughness value, typically expressed in micro-inches or microns. |
| Automation | A broad and often undefined term in finishing—context and clarity are essential. |
III. State of the Finishing Department
A. Continued Reliance on Hand Finishing
Despite advancements in upstream manufacturing, many components from industries such as aerospace, medical, and firearms are still hand finished—often with files, sandpaper, Dremel, and buffing wheels. Investment in modern finishing equipment can reduce labor costs, improve consistency, lower rejection rates, and enhance component performance.
Outdated hand finishing operations, still being used today, are becoming harder to maintain staffing.
B. Advancements in Finishing Equipment
The term “tumbling” is often misused to describe any mass finishing operation. In reality, it refers specifically to the earliest barrel finishing technology.
Vibratory Finishing
High-Energy Equipment
Burnishing Equipment
Drag Finishing
- Vibratory Finishing: Utilizes offset counterweights in a bowl or tub to create rotational movement of parts and media. Outside of tumblers, this is the oldest mass finishing equipment, however, advances in configuration and functionality have been developed.
- High-Energy Equipment: These systems use centrifugal force and programmable motion for faster, more consistent finishing. ‘Harperizing’ is a brand-derived term, much like ‘Kleenex,’ referring to various high-energy centrifugal barrel finishing systems. Within this sector of high energy equipment, we also include high energy centrifugal disc finishing equipment. Each variation having certain performance or operational benefits over the other.
- Burnishing Equipment: This is more of a process and or machines, whose purpose is to use a not abrasive media to impart a smooth and or shiny finish with out removal of material. A Special machine for this is called a Roll Burnisher but can also be accomplished in a tumbler, vibratory or a high energy finisher.
- Drag Finishing: Vertical, Horizontal and Automated Drag machines are mass finishing with the difference of multiple parts being mounted to fixtures and dragged through the tub of media, stationary or rotating for deburring, honing or polishing.
C. Lack of Training in Finishing Processes
Mechanical engineering curricula often lack education on component functionality and finishing.
Who can design this component in CAD? (All hands raised)
Who can machine it on a CNC? (Half the hands raised)
Who knows the design has 72 areas that prevent functionality postmachining? (None)
We need both academic and industrial onboarding training that addresses finishing considerations during the design phase. A standardized ISO document could help bridge this gap.
IV. Manufacturing Culture
Before reworking an existing process or developing a new finishing methodology, manufacturers must first evaluate their overall production culture. In other words: how are your facilities and workflows actually operating? Is your finishing department designed around legacy methods, or is it integrated into the rest of your production line?
We must also ask: what does your current manufacturing culture dictate for both legacy products and newly introduced components? Modern finishing decisions—whether process selection or equipment investment—should be shaped by how and where the finishing operation fits into the broader manufacturing strategy. The following models, as outlined in the adjacent chart, help identify how finishing culture impacts productivity and decision-making by weighing priorities such as processing time, cost, quality, and training requirements.
| Finishing Operation | Most Important | Least Important | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Processing Time | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
| Quality of Finish | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
| Cost of Finish | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
| Employee Training | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
| Material Cost | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
| Maintenance | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
When choosing the optimal finishing equipment for your production needs and you have accessed your manufacturing culture, the following chart should give you some choices to think about for the correct application:
The “Mall” Model: This refers to the traditional, centralized finishing room—a separate space where parts are routed from all over the facility. Components are typically produced in various departments and sent to the finishing room in batches, where they enter a queue with other products. Equipment selection and process methods are chosen based on output quantity, part type, and scheduling requirements.
Cellular Finishing:: This model moves the finishing process closer to where components are actually produced. Finishing may be located adjacent to a machining center, a CNC department, a quality control cell, or even shipping. This setup reduces part travel and aligns finishing with the flow of production. Equipment and process choices are made based on immediate production needs, improving communication and efficiency.
One-Piece Flow:: This approach further refines the cellular model. Finishing is fully integrated within the machining cell and designed to match the takt time of individual components. While this setup promotes fast throughput and lean manufacturing, it also limits the number of viable finishing technologies—only those that can match the production pace are feasible.
EHS Regulations:: Environmental, health, and safety guidelines now heavily influence how finishing technologies are implemented. Considerations include wastewater disposal, dust control, fire hazards, and worker safety—each of which must be factored into the design and layout of any updated finishing department.
V. Examples
Example 1: Medical Bone Screw Manufacturer
This company produced batches of 2,000 bone screws per SKU using multiple specialized lathes. Once machined, each batch was routed to a centralized, Mall-style finishing room where large vibratory finishers handled deburring. Parts were queued alongside many other batches, with a complex communication system required to prioritize scheduling. After deburring, the parts proceeded to passivation and inspection.
Problem:
The entire process took an average of 21 days. If too many screws failed inspection, the entire batch would be rejected—triggering another 21-day cycle to replenish inventory.
Solution:
Deburring was moved to a cellular station with a high-energy centrifugal disc finisher. Co-located with the lathes, this system matched the takt time for 200-piece batches and included integrated cleaning and drying.
Results:
- Eliminated the need for separate deburring labor—the CNC machine operators handled the mass finishing.
- Removed the need for complex communication and scheduling.
- Reduced processing time from 21 days to just 4 days.
- Lowered rejection rates by 10x and shortened restock time to 4 days.
Example 2: New Pistol Model – Firearms Manufacturer
Before launching a new product, the production manager—tasked with implementing Lean Manufacturing—anticipated high initial demand. A One-Piece Flow system was selected for its efficiency and scalability.
This approach established the takt time requirements for finishing processes such as deburring, polishing, blasting, cleaning, and laser etching. Equipment layout was designed prior to production, ensuring synchronization with the machining department.
Results:
- First articles reached the market faster than expected, boosting early adoption and order volume.
- Quality control improved due to centralized finishing and final assembly.
- Machining feedback loops led to better part quality from the outset.
Cellular finishing layout designed for takt time alignment and streamlined production flow.
Conclusion
Bring engineering back into your finishing operations.
A modern, well-integrated finishing department doesn’t just make your job easier—it makes your product more competitive.
In the next article we will discuss the nuances with the term Automation with regards to your mass finishing.
by Steve Alviti Sr
Contributing Editor MFN and
President and Owner of Bel Air
Finishing Supply Corporation