A DIY-compatible, low-cost method for producing conductive carbon electronics on Kapton tape using a desktop laser engraver.

LaserPecker 3 Kapton / polyimide Benchtop fabrication

Abstract

Background

Laser-induced graphene is a three-dimensional, porous carbon nanomaterial produced by irradiating carbon-rich precursors with a laser—typically a CO₂ laser—in ambient air. First demonstrated in 2014 at Rice University by Lin, Tour & co-workers, the photothermal process converts the sp³ carbon of polyimide directly into sp² graphene networks without additional chemical reagents [1]. The resulting porous film is bonded to the polymer substrate, so it can be patterned in a single, mask-free step by simply rastering the laser beam.

The dominant mechanism is photothermal conversion: laser absorption heats the polymer locally above its decomposition temperature, releasing nitrogen and oxygen while reorganizing the remaining carbon into defective, few-layer graphene sheets. By adjusting laser wavelength, fluence, scanning speed and atmosphere, the resulting morphology can be tuned from isotropic porous structures to anisotropic cellular or woolly fibers. This customization permits control of electrical conductivity, capacitance, wettability and surface area, yielding flexible electrodes with thicknesses on the order of tens of microns.

Applications in the literature

Because LIG can be produced on flexible polymer films in ambient air with no wet chemistry, it has become a platform material for low-cost electronics. Reported applications include in-plane microsupercapacitors with specific capacitances above 4 mF cm⁻² [1], electrochemical sensors for heavy metals and metabolites [2], strain and pressure sensors for rehabilitation monitoring [3], thermoelectric foams for self-powered sensing [4], and laser-healed conductive traces with improved crystallinity [5]. More recent work has also transferred LIG onto elastomers as thin as 6.7 µm for large-area electronic skins [6]. These diverse uses all exploit the same core advantage: a conductive, high-surface-area carbon layer generated in a single laser-writing step.

Experimental Methods

Substrate preparation

Kapton sheets were cut into 40 mm × 40 mm squares. Surfaces were mechanically abraded with fine sandpaper to promote graphene and porous-structure formation, then cleaned with ethanol to remove contaminants that could lead to inhomogeneous conversion.

Fabrication setup

After 5 minutes of air drying, each sample was secured with Kapton tape to the bottom plate of a LaserPecker 3 laser engraver. The print area was aligned to the top-left corner of the software preview.

Parametric screening

A series of laser passes were executed at varying depth/power percentages, focal distances, resolutions, and pass counts to identify the processing window that yields conductivity.

Process Parameters and Formulas

Table 1. Parameter Legend

Symbol	Description	Units / Remarks
P	Laser power	W
P(%)	Relative power setting	Fraction or %
β / βmax	Beam-width ratio	Dimensionless
f / #	Optical F-number	Dimensionless
h	Hatch spacing (line spacing)	µm (convert to mm for energy-density calculations)
Res	Resolution code	e.g., 1k, 2k, 4k
S	Scan speed	mm/s
Smax	Max scan speed at given resolution	mm/s
Depth(z)	Process depth / penetration	Reciprocal of Smax as written
Dep	Depth factor	Dimensionless
Ed	Areal energy density	J/mm²
D	Duty cycle	%

Table 2. Core Formulas

Category	Expression	Notes
Power scaling	P(%) = (β / βmax) · (f / #)	Annotated “pwr width (ns)”; pulse-width dependence is noted but unspecified.
Full-power reference	P(100%) = 1 W	100 % scale = 1 W.
Hatch spacing	h = (1 / Res) · 100 µm	—
Speed limits	Smax(1k) = 800 mm/s Smax(2k) = 400 mm/s Smax(4k) = 200 mm/s	Units: mm/s.
Depth (reciprocal)	Depth(z) = 1 / Smax(Res)	Written as a direct reciprocal; a proportionality constant may be required.
Depth factor	Dep = 100 / Res	Used in the LCD shortcut.
Energy density (full)	Ed = P / (S · h)	Use consistent units: P [W], S [mm/s], h [mm].
Energy density (LCD)	Ed = P(%) · Dep	Shortcut valid when parameters are aligned to the full formula.

Results

Table 3. Parametric Screening Data

Depth (%)	Power (%)	Focus (mm)	Conductive	Resistance (Ω/mm²)	Passes	Resolution
100	80	13.8	No	—	1	1k
100	100	13.8	No	—	1	1k
100	100	14.5	No	—	1	1k
100	100	13.0	No	—	1	1k
100	100	14.8	No	—	1	1k
100	100	15.2	No	—	1	k
100	100	14.2	Yes	8	2	1k
20	100	14.2	Yes	20	2	4k

Discussion

The parametric sweep reveals that conductive traces were achieved only at a focal distance of 14.2 mm, using 2 passes at 1k resolution and 100 % power. At focal distances between 13.0 mm and 15.2 mm—regardless of power or depth percentage—no conductivity was observed with single-pass processing at 1k resolution. Sheet resistance values of 8 Ω/mm² and 20 Ω/mm² were recorded for 100 % and 20 % depth settings, respectively, indicating that once the focal window and resolution are correct, the depth percentage modulates the final resistance.

Conclusion

This note demonstrates a simple, DIY-compatible route for fabricating laser-induced graphene circuits on Kapton tape using a desktop laser engraver. By clarifying the relevant process parameters and formulas, and by identifying the critical focal distance and resolution required for conductivity, this work provides a reproducible starting point for producing low-cost, flexible, and biocompatible carbon electronics.

References

1. J. Lin et al., “Laser-induced porous graphene films from commercial polymers,” Nat. Commun. 5, 5714 (2014). DOI: 10.1038/ncomms6714
2. K. H. Chen et al., “Understanding Baseline Drift in Laser-Induced Graphene Electrodes and Its Impact on Heavy Metal Detection by Anodic Stripping Voltammetry,” J. Electroanal. Chem. (2026). PMID: 42182954
3. L. Huang & N. Zhao, “Laser-Induced Graphene-Polyimide Film Sensor for Simultaneous Lip Electromyography and Pressure Monitoring in Personalized Rehabilitation,” J. Vis. Exp. (2026). PMID: 42149837
4. L. Yang et al., “Thermoelectric porous laser-induced graphene-based strain-temperature decoupling and self-powered sensing,” Nat. Commun. 16, 1–12 (2025).
5. “Flash healing of laser-induced graphene,” Nat. Commun. 15, 1–11 (2024).
6. Y. Lu et al., “Universal modulus-free transfer of scalable laser-induced graphene for electronic skins,” Nat. Commun. 17, 1–12 (2026).

Article · Soft Robotics

The Twisted Helical Tendons in Soft Continuum Robots

How helical tendon systems are redefining dexterity, safety, and adaptability in soft continuum robotics.

Soft Robotics Helical Tendons Continuum Manipulators

The world of robotics is experiencing a quiet revolution, one that draws inspiration from nature’s most elegant solutions while pushing the boundaries of what machines can achieve. At the forefront of this transformation are twisted tendon soft continuum robots—a groundbreaking technology that promises to redefine how robots move, grasp, and interact with their environment.

Unlike the rigid, angular movements of traditional industrial robots, these revolutionary machines flow like living creatures, adapting their entire body to wrap around objects with the grace of an octopus tentacle or the precision of an elephant’s trunk. The secret lies in their innovative helical tendon system, a design breakthrough that enables unprecedented levels of dexterity, safety, and versatility.

Nature’s Blueprint: The Biological Inspiration Behind the Innovation

For millions of years, nature has perfected the art of flexible manipulation through creatures like octopuses, elephants, and snakes. These animals achieve remarkable dexterity without rigid joints, instead relying on muscular hydrostats—structures that change shape through coordinated muscle contractions.

Researchers at institutions like Italy’s prestigious Scuola Superiore Sant’Anna have been studying these biological marvels, particularly focusing on how helical muscle arrangements enable complex twisting and grasping motions. The octopus arm, for instance, can simultaneously bend, extend, and twist while maintaining the ability to grasp objects along its entire length—a capability that traditional robots have struggled to replicate.

The elephant trunk presents another fascinating model, combining incredible strength with delicate precision. It can lift massive logs or carefully pluck a single leaf, all while navigating complex three-dimensional spaces. This versatility stems from the trunk’s unique muscular architecture, where longitudinal, transverse, oblique, and radial muscles work in harmony to create fluid, adaptive motion.

The Game-Changing Innovation: Helical Tendon Technology

The breakthrough that sets these new soft continuum robots apart lies in their revolutionary helical tendon system. While traditional soft robots have relied on straight cables (coaxial tendons) that only allow basic bending and extending motions, the introduction of helical tendons—cables that spiral around the robot’s core in a corkscrew pattern—has unlocked a world of new possibilities.

How Helical Tendons Work

The helical tendon system operates on a elegantly simple yet powerful principle. These twisted cables don’t just pull in straight lines like conventional systems; instead, they create complex three-dimensional forces that enable:

• Full 360-degree twisting motion around the robot’s central axis
• Enhanced grasping capability along the entire length of the robot’s body
• Improved workspace dexterity through coupled bending and twisting motions
• Superior force transmission due to the helical geometry’s mechanical advantages

Research has shown that helical tendons significantly increase both the dexterity and working space of continuum robots, enabling them to avoid obstacles and roll around objects while exerting considerable forces. This represents a fundamental leap forward from traditional designs that were limited to basic bending motions.

Performance Superiority: The Numbers Don’t Lie

Recent research has demonstrated the substantial performance advantages of helical tendon systems over traditional approaches across multiple metrics. The improvements are particularly striking in several key areas:

Workspace and Dexterity Improvements

Studies comparing helical and traditional tendon systems reveal dramatic improvements in workspace capabilities. Helical systems achieve:

• 35% larger workspace compared to traditional coaxial systems
• Infinite twisting capability versus zero twisting in conventional designs
• 95% grasping success rate compared to 65% for traditional systems
• 25% improvement in workspace dexterity through enhanced degrees of freedom

Force and Precision Metrics

The mechanical advantages of helical geometry translate into superior force transmission and precision control:

• 37.5% increase in force output due to improved mechanical leverage
• Sub-millimeter positioning accuracy in controlled environments
• 50% improvement in environmental adaptability for complex terrains
• Enhanced load-bearing capacity up to 260 times the robot’s own weight in some configurations

Real-World Applications: From Operating Rooms to Orchards

The versatility of twisted tendon soft continuum robots has opened doors to applications across numerous industries, each leveraging the technology’s unique advantages.

https://www.frontiersin.org/journals/robotics-and-ai/articles/10.3389/frobt.2020.00119/full

https://www.sciencedirect.com/science/article/abs/pii/S0921889025000740

Current Limitations

Despite their impressive capabilities, twisted tendon soft continuum robots face several challenges that researchers are actively addressing:

Modeling Complexity: Longer robot configurations introduce complexities in modeling and control, particularly regarding the coupling between bending and twisting motions. High tangential forces can cause unintended interactions between motion modes.

Computational Requirements: Real-time control of multiple helical tendons requires significant computational resources, especially for longer multi-segment robots.

Material Durability: Long-term operation can lead to material fatigue and hysteresis effects, particularly in the silicone components. Research indicates up to 75% reduction in repeatability errors can be achieved through improved materials and control strategies.

Scalability: While modular design enables scalability, longer configurations present challenges in maintaining precise control and preventing unwanted coupling between segments.

Future Research Directions

The field is rapidly evolving with several promising research directions:

Artificial Intelligence Integration: Machine learning and artificial intelligence approaches show promise for model-free control strategies, potentially eliminating the need for complex mathematical models.

Advanced Materials: Development of new smart materials with improved durability, responsiveness, and self-healing capabilities could address current material limitations.

Hybrid Designs: Combining soft continuum elements with rigid components in hybrid architectures may optimize performance for specific applications.

Multi-Robot Coordination: Coordinated control of multiple soft continuum robots could enable complex manipulation tasks beyond the capabilities of individual units.

The Path Forward: A Flexible Future

As we stand at the threshold of a new era in robotics, twisted tendon soft continuum robots represent more than just a technological advancement—they embody a fundamental shift toward machines that work with us, not just for us. By drawing inspiration from nature’s most elegant solutions and combining them with cutting-edge materials science and control theory, these robots promise to extend human capabilities in ways we’re only beginning to imagine.

The journey from laboratory prototype to widespread industrial deployment is accelerating. Research institutions worldwide are building on the foundational innovations established by pioneers in the field, continuously improving performance, reliability, and cost-effectiveness. Each breakthrough brings us closer to a future where robots seamlessly integrate into our daily lives, handling delicate tasks with the finesse of a master craftsman and the reliability of advanced automation.

The implications extend far beyond individual applications. As these robots become more capable and affordable, they will enable new forms of human-robot collaboration, open previously inaccessible markets, and solve problems that have long seemed intractable. From the precision required in microsurgery to the scale needed for agricultural automation, twisted tendon soft continuum robots are poised to transform industries and improve lives.

The future is flexible, adaptive, and alive with possibility. And with researchers around the world building on these foundational innovations, that future is closer than we think. The age of truly intelligent, responsive robotics has begun, and it’s being written in the language of twisted tendons and soft intelligence.

This research represents a collaborative effort between multiple engineering disciplines to push the boundaries of what’s possible in robotic design and control, with foundational work conducted at institutions like the Scuola Superiore Sant’Anna’s Institute of BioRobotics in Italy and advanced implementations at leading universities worldwide.

Article · Soft Robotics

Soft Robotics: From Squishy Muscles to Sustainable Machines

A survey of the field’s origins, core technologies, emerging applications, and sustainable future.

Soft Robotics Actuation Sustainability

Soft robotics is reshaping how engineers think about motion, safety, and adaptability. By swapping rigid metal for compliant polymers, textiles, and gels, researchers are building machines that can squeeze through rubble, assist surgeons, harvest strawberries, and biodegrade when their job is done. This article surveys the field’s origins, core technologies, emerging applications, and sustainable future.

1. Why “Soft” Matters

Soft robots borrow principles from octopus arms, elephant trunks, and human tissue. Their hallmark properties are:

• Compliance and safety – Deformable bodies absorb impacts and reduce injury risk.
• Morphological intelligence – A soft structure can passively adapt to complex environments, off-loading computational burden.
• Versatility of actuation – Pneumatics, tendon pulls, dielectric elastomers, shape-memory alloys (SMAs), and magnetic fields provide diverse motion modes.

Traditional industrial robots thrive on speed and precision in structured settings; soft robots excel when adaptability, gentle handling, or unstructured terrains dominate.

2. Actuation Technologies

Technology	Working Principle	Typical Strain	Pros	Cons	Recent Milestone
McKibben pneumatic muscles	Pressurized inner bladder in braided mesh contracts	20-30%	High force-to-weight, simple fabrication	Air supply, limited stroke	Chain-link actuator boosts contraction >50%
Pneumatic networks (PneuNets)	Inflating internal chambers bends elastomer fingers	>100%	Lightweight, food-safe silicones	Compressors, out-of-plane twist	Torsion-resistant layer lifts 5 kg payload
Dielectric elastomer actuators (DEAs)	Electric field squeezes thin elastomer, creating area expansion	10-50%	Fast response, silent	kV voltages, breakdown	Fully biodegradable electrohydraulic DEA gripper lifts oranges
Shape-memory alloy wires	Joule heating triggers crystalline phase change and contraction	4-8% (wire)	Compact, silent	Slow cooling, hysteresis	Hybrid SMA–pneumatic bimorph for haptics (CHI 2024)
Magnetic composites	Embedded particles steer with external fields	Up to curvilinear motion	Remote untethered control	Requires magnetic setup	Catheter with in-situ force sensing for heart ablation

3. Modeling and Control Challenges

Unlike rigid arms that rely on a handful of joints, soft manipulators have theoretically infinite degrees of freedom. Two dominant approaches help tame this complexity:

1. Piecewise Constant Curvature (PCC) – Approximates the backbone as a series of circular arcs; simple but neglects torsion and shear.
2. Cosserat Rod Theory – Treats the body as a continuum rod; recent finite-element and real-time solvers bring PDE models into control loops.

Machine learning now complements physics models: deep reinforcement learning tunes Jacobian gains for tendon-driven arms, outperforming ideal model-based controllers in noisy settings.

4. Application Highlights

4.1 Medical Robotics

• Magnetic soft catheters navigate tortuous vasculature and measure contact forces for safer ablation.
• Origami-based inflatable endoscopes bend 200° at <20 kPa for upper-GI inspection.
• Hydrogel “octobots” could deliver drugs or perform in vivo biopsies powered by peroxide microfluidics.

4.2 Industrial Automation

• Food-grade silicone grippers from SoftGripping and SRT handle irregular produce without bruising; torsion-controlled fingers now grasp 5 kg sacks.
• Pneumatic hands integrated on cobots sort cosmetics, flex batteries, or delicately package baked goods.

4.3 Agriculture & Environment

• Strawberry-harvesting soft grippers adapt to fruit variability, reducing waste.
• Biodegradable rice-paper bots promise single-use soil sensors that decompose in 32 days, leaving no plastics behind.

4.4 Wearables & Haptics

• Knitted textile actuators incorporate pneumatic bellows to assist stroke patients with grasping.
• SMA-reinforced inflatable sleeves provide nuanced squeeze feedback for social robots and VR devices.

5. Toward Sustainable Soft Robotics

Environmental concerns drive a shift from long-lasting silicones to biodegradable elastomers, celluloses, and photodegradable networks. Key research directions:

• Green material libraries – Rice paper, gelatin–oil films, PLA blends, and cellulose origami modules match mechanical performance of PDMS.
• On-demand end-of-life – UV-triggered cleavage converts silicone bodies to inert oils for safe disposal.
• Closed-loop circularity – Recyclable liquid metal circuits and water-based hydraulic fluids minimize e-waste.

6. Future Outlook

1. Integration – Embedding soft sensors, stretchable batteries, and logic for fully untethered autonomy.
2. Scalability – High-throughput 3-D printing and machine knitting accelerate mass production.
3. Standardized modeling – Unified Cosserat-based toolkits will speed controller design across platforms.
4. Regulatory pathways – Clinical translation of soft catheters and exosuits requires rigorous safety validation.
5. Sustainability metrics – Life-cycle assessments will guide material choice and disposal strategies.

Soft robotics is rapidly evolving from lab curiosity to real-world technology: gripping croissants, steering within hearts, and even self-vanishing in compost piles. As materials, modeling, and actuation converge, expect a new generation of machines that are safer, greener, and more adaptable than ever before.