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DELRIN ® CASE STUDY
Delrin ® – in Humanoid Robotics
Polymers Are Rewriting the Rules of Mechanical Design
Many major engineering platform shifts have been accelerated by polymers replacing metal where it no longer makes
sense. Automotive eliminated many metal bearings, bushings and tribology parts with engineering thermoplastics —
cutting weight and cost while improving reliability. Medical devices replaced several machined steel components with
acetal and PEEK — achieving tighter tolerances and lower friction at a fraction of the part cost. Electronics abandoned
die-cast housings for injection-molded plastics — enabling miniaturization for innovation in smart phones. In each case
the driver was the same: polymers delivered better system-level performance at lower cost, with design freedom that
metal could not match. Humanoid robotics is the next frontier, and Delrin® is a material engineered for this transition.
The Challenge:
Building Robots That Work in the Real World
Humanoid robots are no longer lab curiosities. Market-leading
humanoid OEMs are transitioning from pilot programs to early
production — and the materials choices being made right now will
define which robots survive the move from demo to deployment.
The engineering demands are extraordinary. A humanoid robot must
be lightweight yet strong, operate through millions of reliable cycles,
tolerate continuous mechanical stress, maintain tight tolerances in
compact joint geometries, and do all of this at a cost that supports
commercial scale. No material category is more challenged by these
demands than the structural and mechanical components found in
robot hands, wrists, forearms and joints.
Why Delrin®? — The Engineering Case
A humanoid
robot must
be lightweight
yet strong.
Delrin® is a high-performance acetal homopolymer resin with a
unique combination of properties that makes it particularly suited to
the demanding mechanical environment inside humanoid robots and
robotic hands.
The following hardware bottlenecks may concern humanoid and robot
hand manufacturers:
Bottleneck
Impact on Production
Dexterity & manipulation
reliability
~70% simple grasp success today; task
failures destroy ROI
Component weight in
distal joints
Every gram in hands/fingers increases arm
inertia & energy draw
Material wear & fatigue
Hands must survive millions of cycles —
metal and printed plastics fall short
Cost at scale
Actuators alone are 50–60% of BoM; every
other component must work harder on cost
DELRIN ® CASE STUDY
Delrin ® – in Humanoid Robotics
Mechanical Performance
• Low coefficient of friction and excellent wear resistance
(Figure 2) — self-lubricating in dry sliding contact, ideal
for gear teeth, cam surfaces, and bearing surfaces
where grease is impractical
• High stiffness-to-weight ratio — significantly lighter
than aluminum with competitive specific strength
for non-load-bearing structural parts
• Outstanding fatigue resistance (Figure 1) — maintains
performance through repeated cyclic loading,
critical for finger flexion, gripper actuation and
linkage mechanisms
• Good impact resistance at room and low temperatures
(Figure 3) — survives drop events and shock loading in
robot falls
Figure 1. Flexural fatigue strength after one
million cycles
Figure 3. Impact strength at ambient (23 °C) and
sub-ambient conditions (-30 °C)
Notched Charpy Impact Strength (kJ/m2)
Delrin®
PA66 +
30% GF
cPOM
PBT
PA66
Flexural fatigue strength for 1 million cycles (MPa)
Wear Rate (mm3/Nm x 10-6)
PPO
PA6
Delrin®
0.1
0.2
0.3
Dynamic Coefficient of Friction (-)
a
PV = 0.0675 MPa.m/s (P = 0.27 MPa and V = 0.25 m/s)
Delrin®
500P
Delrin®
100P
PA66
PA66+
30% GF
PPA+
30% GF
PEEK
PBT
Others
Dimensional Stability
• Low moisture absorption vs. nylon (Figure 4) —
maintains tight tolerances in humid environments
and through thermal cycling
Figure 4. Moisture absorption of various plastics
Delrin®
lubricated
• Predictable, consistent behavior across operating
temperatures from –40°C to +90°C — matching the
thermal envelope identified in humanoid operational
specifications
PBT
At 23º C
At -30º C
Delrin ®
Figure 2. W
ear rate and dynamic coefficient of
friction comparison for various plastics on a
steel countersurfacea
0.4
0.5
PA66
PPA
Delrin®
PEEK
0.5
1.5
Moisture absorption (%)
2.5
DELRIN ® CASE STUDY
Delrin ® – in Humanoid Robotics
Chemical & Environmental Resistance
• Resistant to fuels, solvents and cleaning agents (Table 1) — suitable for robots operating in industrial
and food-adjacent environments
• Does not require surface treatment or coating to achieve functional performance
Table 1. Resistance to common chemicals, cleaners, and greases
Chemical / Media
Delrin®
Nylon (PA66)
unfilled
Nylon (PA66)
30% GF
PBT
PEEK
PPA
Alcohols (Isopropyl alcohol, Ethanol)
Polar Solvents (Acetone, Methyl Ethyl Ketone)
Hydrocarbon solvents (Heptanes, Hexanes, Xylenes)
Bleach (NaOCl, typical dilute disinfecting)
Hydrogen peroxide (3% disinfecting)
Detergents (pH ~5–9)
Greases (Mineral oils / PAO / silicones)
= Compatible,
= Moderately compatible,
= Poor compatibility
Two Paths to Market: Prototype Fast, Scale Smart
One of Delrin’s commercially compelling advantages is that it supports the full product development lifecycle —
from the first prototype to high-volume production — using the same material and the same performance baseline.
Path 1: Machinable Stock Shapes for R&D and Low Volume
Path 2: Injection Molding for Cost-Effective High Volume
Delrin is available in rod and sheet stock that can be
CNC-machined to tight tolerances quickly and costeffectively. For humanoid OEMs and their supply chains,
this means:
As production scales — from hundreds to tens of thousands of units — Delrin® transitions seamlessly into injection molding, enabling:
®
• No tooling investment — parts are in hand within days,
not weeks
• Design iteration is fast — revise CAD, re-machine, retest;
the material doesn’t change
• Performance is production-representative — properties
of machined Delrin® closely match molded Delrin®,
so validation data carries forward
• Ideal for finger phalanges, palm housings, pulley guides,
tendon routing channels and sensor mounts — all
components that change frequently during development but need real-world mechanical behavior
For small companies, start-ups and university research
teams building open-source humanoids on limited
budgets, machinable Delrin® stock shapes offer a direct
route from design file to functional hardware without the
overhead of casting or forming tools.
• Dramatic per-part cost reduction — a component
that is expensive to machine can be produced much
more economically through molding, especially at
higher volumes
• One-shot net-shape manufacturing — complex
geometries, undercuts, snap fits and integrated
features produced in a single operation with no
secondary machining
• Consistent, repeatable quality — injection molding
tolerances are well-suited to gear teeth, bearing
housings and precision linkage components
• Cycle times of seconds — supporting the production
velocities humanoid OEMs will need as they scale
toward thousands of units per month
This dual-path capability — prototype in machinable stock, scale in injection molding — eliminates the material transition
risk that plagues teams that develop in one polymer and produce in another.
DELRIN ® CASE STUDY
Delrin ® – in Humanoid Robotics
Specific Applications in Humanoid Robots
Component
Why Delrin®
Finger phalanges & knuckle joints
Low weight, machinability, fatigue resistance through millions of flexion cycles
Tendon routing guides & pulleys
Self-lubricating, low friction, wear-resistant contact surfaces without grease
Gripper jaw bodies & end effectors
Stiff, dimensionally stable, easy to machine or mold to complex profiles
Wrist & forearm housings
Lightweight alternative to aluminum; moldable to net shape at volume
Gear blanks & small spur gears
Excellent for low-to-medium load gear sets in finger actuators; runs dry
Sensor mounts & PCB housings
Dimensional stability, electrical insulation, snap-fit integration
Cable management clips & guides
High fatigue life under repeated flex, low friction on cable jackets
The Cost Argument: Materials Must Scale with the Market
According to in-house assessments, the market inflection point for humanoid adoption is widely cited at ≤ US$20,000
per unit. Achieving that threshold requires every component category to be optimized for cost at volume. Engineering
plastics like Delrin® play a direct role in closing that gap.
Replacing machined aluminum housings and structural brackets with molded Delrin® parts can deliver significant
cost reduction on eligible components while maintaining functional performance. In a typical robot with
40+ joints and hundreds of mechanical sub-components, even modest per-part savings compound rapidly across
the BoM.
Delrin® does not replace metals in high-load structural joints or actuator cases, but it competes decisively in the large
population of medium- and low-load components that make up a significant share of both cost and part count.
Property
Delrin®
Nylon (PA6/66)
PEEK
PPA
Moisture absorption
Low
High
Low
Low
Machinability
Excellent
Good
Difficult / costly
Moderate
Dry wear / friction
Excellent
Good
Very good
Moderate
Cost
Low–Medium
Low
Very high
High
Injection moldability
Excellent
Excellent
Specialist
Good
Fatigue resistance
Excellent
Moderate
Very good
Good
For components where cost, machinability, low friction and moisture stability are the governing requirements — which
describes most of the robotic hand and forearm components — Delrin® is the material of choice.
DELRIN ® CASE STUDY
Delrin ® – in Humanoid Robotics
Delrin® delivers 70% of the tensile strength of PEEK at
just 5% of the cost—a 95% cost savings with minimal
performance compromise.
For the vast majority of robotics applications—gears, housings, sliding components, structural brackets—Delrin® meets
the mechanical brief while dramatically reducing material spend.
70%
tensile strength vs PEEK
95%
cost savings vs PEEK
77%
cost savings vs PPA
Data normalized to PEEK baseline. For design-critical applications, consult material data sheets.
Work With Delrin
Whether your team is machining first-article prototypes for a robotic hand or qualifying an injection-molding program
for a fleet-scale humanoid deployment, Delrin offers:
• Stock shapes such as rods or plates for small volume and lab-scale projects
• Application engineering support for joint design, tolerance specification and grade selection
• Material data for simulation and FEA validated against real test specimens
• Processing support to optimize manufacturing efficiency and de-risk the ramp-up
•
Grades for specialized requirements (i.e. easy processing, impact modified, low wear & low friction, reinforced,
grades for regulated industries, and sustainability)
Contact us:
www.delrin.com
Robotics Landing Page:
www.delrin.com/robotics
Technical Data Sheets:
www.delrinmaterialcenter.com
Delrin – Engineering the Future, Together
To learn more, contact your Delrin representative or visit Delrin.com..
Delrin® is an industry-leading premium industrial polymer business. Grounded in strong innovation, Delrin is a category creator with a longstanding reputation for quality, reliability, supply and
product performance. The iconic Delrin brand, coupled with proprietary technology and deep application expertise, make us a leader in the high-end engineering polymer market. Delrin has exciting growth prospects from exposure to automation, actuation, healthcare, mobility and consumer applications.
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