Centrifugal Iso-Finishing Technology is used on 3D Printed and conventional CNC precision machined components for deburring, finishing and polishing. It is a high-speed, high-quality hands-free finishing method that produces highly refined surface finishes in a fraction of the time required by other equipment (10 times faster, in many cases) Free sample finishing of your parts is available, contact Dave Davidson at ddavidson@deburring-tech-group.com

1. Centrifugal Iso-Finishing
Technology for Additive and
Subtractive Manufactured Parts
Dave Davidson
Deburring/Finishing Technologist
ddavidson@deburring-tech-group.com
https://dryfinish.wixsite.com/iso-finish
Past-Chair, Deburring/Finishing Technical Committee
Society of Manufacturing Engineers

2. Table of
Contents
Part 1 – Mass Finishing Process
Primer
Part 2 – Centrifugal Iso-Finishing
Process Principles
Part 3 - Additive Manufactured
Part Applications
Part 4 - What about other parts?

3. Part 1
What is Mass
Finishing?
• Mass finishing is a term used to
describe a group of abrasive industrial
processes by which large lots of parts
or components made from metal or
other materials can be economically
processed (edge or surface finished) in
bulk.
• All mass finishing processes utilize a
loose or free abrasive material referred
to as media within a container or
chamber of some sort. Energy is
imparted to the abrasive media mass
by a variety of means to impart motion
to it and to cause it to rub or wear
away at part surfaces.

4. What edge and
surface effects
can be
created?
• This processing is performed to achieve one or several
of a variety of edge and surface effects:
(1) Edge effects: Deburring, edge-break, radius
formation
(2) Surface effects: removal of surface contaminants
from heat treat and other processes, pre-plate, pre-
paint or coating surface preparation, blending in
surface irregularities from machining or fabricating
operations, producing reflective surfaces with
nonabrasive burnishing media, refining surfaces,
developing super-finish or micro-finish equivalent
surface profiles, developing compressive stress with
burnishing media to improve fatigue or wear
resistance, smoothing rough-cast or 3D Printed
Parts, improve isotropicity, promote negatively
skewed surface profiles for cooperating parts,
minimizing hand-deburring operations

5. Why Mass
Finishing?
• Nearly all manufactured parts or
components require some measure of
surface refinement prior to final assembly,
or the final finish or coating required to
make the parts acceptable to the
consumer or end-user.
• Most manufacturing companies who
employ mass finishing techniques do so
because of the economic advantages to be
obtained, especially when compared with
manual deburring and surface finishing
techniques.
• Mass finishing processes often reduce or
eliminate many procedures that are labor-
intensive and require extensive part
handling.

6. Mass
Finishing
Versatility
Although each of the mass finishing process types
carries with it a unique set of process strengths and
weaknesses, all of them are sufficiently versatile to be
able to process a wide variety of part types
successfully.
A plethora of abrasive media types, sizes, and shapes
makes it possible, in many cases, to achieve very
different results within the same equipment, ranging
from heavy grinding and radiusing to final finishing.
Components from almost every conceivable type of
material have been surface conditioned using mass
finishing techniques including ferrous and nonferrous
metals, plastics, composition materials, ceramics, and
even wood.

7. Mass
Finishing
Cautions
Despite the immense versatility of these types of processes, some
potential process limitations should be noted. It can be difficult to
selectively treat certain part areas to the exclusion of other areas,
which might have critical dimensional tolerance requirements. Unless
masked or fixtured, all exterior areas of the part will be affected by
the process to a greater or lesser degree, with effects on corners and
edges being more pronounced than those on flat areas, and with
interior holes, channels, and recesses being relatively unaffected in
the more common processes.
Care must be exercised in media size, shape selection, and
maintenance to prevent media lodging in holes and recesses, which
might require labor-intensive manual removal. Some parts have
shapes, sizes, or weights that may preclude them from being finished
in some mass finishing processes because of the risk of impingement
from part-on-part contact or of nesting due to certain features of the
parts interlocking together when in proximity. Additionally, most
processes that use water in conjunction with the abrasive media
create an effluent stream, which must be treated prior to discharge
into a municipal sewage or another disposal.

8. Mass
Finishing
Equipment
One of the more obvious factors influencing mass finishing processes
is equipment selection. There are five major equipment groups as
follows, two of these are low energy methods, two are high-energy
and one is dependent on part fixturing and is considered a high
energy method variant.
Barrel, vibratory, centrifugal barrel, centrifugal disk, and spin/spindle
finishing.
The first four groups are primarily used with parts immersed within a
body of abrasive media and are capable of some independent
movement within that mass. On occasion, fixturing or some
processing segmentation may be used to isolate delicate or critical
parts from each other. Part-on-part contact may also be minimized by
using higher media-to-part ratio combinations. Common media-to-
part ratios for noncritical parts run anywhere from 1:1 to 1:4 by
volume. Parts with a higher need for cushioning and protection may
utilize media/part ratios as high as 10:1 to 15:1.

9. Mass Finishing
– Part of the
Manufacturing
Process
Much time and money can be saved both in mass finishing
process operations and in process development if finishing
considerations are given sufficient weight at the design,
production, and quality control stages. Although it is a rule
more breached than observed, it should be noted that
mass finishing processes are not, and were never intended
to be, methods for rectifying errors made in earlier stages
of the manufacturing process.
It should be equally obvious that processes developed for
parts made with tools and dies that are sharp will
no longer produce the same results when that tooling
becomes dull. Mass finishing processes can produce
remarkably uniform results if process parameters are
followed carefully, but this assumes some measure of
uniformity of surface condition for a given part within a lot,
and from lot-to-lot, as received in the finishing area.

10. Part 2 - Centrifugal Iso-
Finishing Principles:
Equipment and
Operations
How does it work?
Machinery
Abrasive and Polishing Media
Processes

11. CC
• Centrifugal Iso-Finishing Technology operation is
similar to the operation of a "Ferris Wheel" but
this Ferris wheel operates at high rotational
speed with the turret swinging the barrels
around its periphery while the barrels counter-
rotate at high speed.
• This motion imparts high centrifugal force to
the parts and media in the processing
chambers. Finishing and polishing work is
performed 10 times faster than conventional
low-energy finishing equipment. On many parts,
single-digit micro-inch Ra surface finishes can
be achieved.

12. Why Both Wet
and Dry
Processing?
• This composite shot shows the interior of a centrifugal barrel finishing machine,
showing a barrel with parts, plastic media and liquid compound to the left, and dry
polishing granules to the right. Once the parts have been smoothed sufficiently
they will be removed from the wet processing compartment and moved to another
compartment with dry polishing.
• Burnishing processes use small heavy non-abrasive media to produce burnished
surfaces. Burnished surfaces have a less polished appearance but develop useful
beneficial compressive stress on the order of shot peening, but without the
undesirable positively skewed surface that shot-peening leaves behind.

13. Video of Wet and Dry Processing with
Centrifugal Iso-Finishing machine
*Connection to internet and YouTube required.

14. Part Application: Centrifugal Iso-Burnishing
Before and after examples of 3 step Centrifugal Iso-Finishing Processing

15. Before and after
Centrifugal Iso-Finishing
with 3D printed
component with both
flat and radiused
features

16. Hands Free Surface Finishing
3D Jewelry Components.

17. Small 3D Part Finishing and
Polishing

18. Centrifugal Iso-Finishing
3D Printed Jewelry
Wet process smoothing and dry process polishing is used for
smoothing and then polishing precious metal jewelry

19. Centrifugal Iso-Finishing 3D Printed Aerospace parts
Parts are finished and polish using a Model HZ-85 with barrel divider panels to isolate parts from each other and
preserve local micro-inch surfaces.. The long length of the barrels make processing large part volumes possible.

20. Before and after examples of 2 step Centrifugal Iso-Burnishing Processes

21. Metal Fatigue
Resistance Benefit –
Centrifugal Iso-
Finishing compared
with shot peening
X-Ray diffraction used graph and
compare residual stress
development between Shot peening
(Dull – Shot peened) and Centrifugal
Iso-Burnishing process (Shiny
Processed)

25. Take-away Point:
Beginning Surface
Roughness =
356.24 µin. Ra

27. Take away point
After processing
Surface Roughness =
12.06 µin Ra

28. Note: More neutral or negatively skewed
surface provides better bearing supporting
surface than the positively skewed surface
shown on surface prior to Centrifugal Iso-
Finish Processing.

30. Comparative Evaluation of 3D Part Surface Finishes.
In this example, the same part (built standard without optimization
to address porosity or features)... was sent with the same
instructions (to polish to the highest finish possible) to five surface
finishing companies. The five different results are shown in the chart
to the right. Results compiled and storyboard developed by Shannon
Van Derren, President, Layered Manufacturing Consultants
(1) Post-Process: Multi-Cycle method, may include wet blasting with follow-up with
vibratory finishing. Multi-hour processing
(2) Rem-Chem: Multi-cycle vibratory processing. Final-Finishing often performed with
acidic accelerant compounds containing oxalic acid, maleic acid or similar material
with non-abrasive media. Outer layer is oxidized with surface peaks and asperities
incrementally removed as processing progresses.
(3) Bel Air: Vendor utilizes a variety of finishing methods, including drag finishing,
centrifugal disc, vibratory and cbf.
(4) Centrifugal Iso-Finishing. Three steps, 3D parts are typically processed (1) Heavy
abrasive smoothing: 1.5-2 hours. (2) Fine smoothing: 30 minutes (3) Final dry
polishing: 30 minutes. Cycle times vary with alloy and part geometry.
(5) Micro-tek: Primarily an unconventional electro-chemical or electro-polishing
technique. Available as a contract finishing service only.

31. Centrifugal Iso-
Finishing
Equipment
• Standard Machine models vary in
capacity from 1.4 cubic feet (40
liters) to 12 cubic feet (330) liters.
• All machine models feature a four
barrel configuration.
• Differing processes can be run in
the machine at the same time.
Typically process A would be run
in barrel numbers 1 and 3, while
process B would be run in barrels
2 and 4 to assure that the machine
is being operated in a balanced
condition.

32. Newly Designed Model HZ-85 used widely in the medical and
aerospace industries for super-finishing and polishing critical parts

33. Equipment
Size and
Configuration
There are two major equipment
families in the machinery line.
(1) Six-inch diameter machines for
processing small to moderately
sized parts.
(2) Twelve-inch diameter machines
for processing large parts and
larger batch volumes of parts

34. Abrasive, Smoothing, Burnishing and Polishing Media

35. Process Development and Sample Part
Processing Operations
Free sample part processing program analyzes and inspects parts,
determines the correct media and machine model and sequence of
operations to produce the required surface finish needed.
To make arrangements for submitting parts into the free sample
part processing program contact Dave Davidson at
ddavidson@deburring-tech-group.com

36. Contract Finishing Process Development
Outsourcing the surface finishing of 3D printed parts is available. Process
engineers will develop Centrifugal Iso-Finishing processes, submit parts
for approval and provide a quotation for post-process finishing.
To submit parts into the free sample part processing program contact
Dave Davidson at ddavidson@deburring-tech-group.com

37. Video: Example of Centrifugal Iso-Finishing Operations
in a Precision Machining Contract Finishing Company
• See the video on YouTube at
https://www.youtube.com/watch?v=dUdKjaysTYM&t=377s

38. Part 4 -What about conventional
or subtractive manufactured part
finishing?
• Centrifugal Iso-Finishing
often performs deburring,
finishing and polishing
functions 10 times faster
than conventional low
energy methods.
• Centrifugal force presses
media against edges and
surfaces with 10 G’s where
conventional finishing
systems are 1 G systems only
• This centrifugal pressure
produces beneficial
compressive stress in some
cases on the order of that
produced by shot peening
but with much more refined
isotropic surfaces

39. High performance automotive engine part finishing, extends engine
service life, improves engine performance

40. Automotive
Cooperating Parts
• Performance Benefits
• Reduced friction
• Increased part durability
• Improved corrosion resistance
• Reduced wear
• Reduced lubrication requirements and
cost
• Improved oil retention
• Reduced contact and bending fatigue
• Improved pitting resistance
• Reduced vibration and noise
attenuation
• Reduced applied torque requirements
• Improved surface finish uniformity
(part-to-part, feature-to-feature, and lot-
to-lot)
• High-quality, micro-finished surfaces
• Reduced Friction Benefits
• Increased fuel economy
• Reduced contact fatigue
• Increased power density
• Lower operating temperature
• Extended mean time between
maintenance overhauls
• Reduced maintenance costs
• Eliminated break-in
• Extended component life
• Reduced metal debris
• Reduced part failures
• Minimized overheating

41. Fit and Function Improvement
Mechanical components and assemblies perform more reliably and smoothly with low micro-inch surface finishes
produced by Centrifugal Iso-Finishing

42. Polishing Aerospace Engine Parts
after Machining and At Overhaul

43. Medical and Dental Part Finishing and Polishing

44. Centrifugal Iso-Finished Components.

45. Finishing and Polishing
Castings

46. Finishing and Polishing
Medical Parts

47. Hands-free polishing of aluminum
castings prior to powder coating

48. Centrifugal Iso-Finishing
Machined Components

49. CENTRIFUGAL ISO-FINISH
Advantages over and above
Superior Edge and Surface Finish
(Before) Ground Surface (After) Centrifugal Iso-Finishing
(1)
(2)
(3)
(1) Compressive stress generation for improved fatigue failure resistance
(2) Isotropic Surfaces for wear and crack resistance
(3) Planarized or plateaued surfaces for improved bearing load surfaces
(After) Centrifugal Iso-Finishing(Before) Cast Surface
High Magnification SEM (Scanning Electron Micro-scope
X-Ray Diffraction
SWLI (Scanning White Light Interferometer)
3D Texture Mapping

50. Follow up. Next step.
Sample Part Processing
For assistance with (free) sample part processing, contract finishing
quotations or equipment and process quotations CONTACT:
Dave Davidson at ddavidson@deburring-tech-group.com