With 8 Generations of Galaxy Fold: Samsung Solved Engineering Problems Before Anyone Else Got Started
In 2019, Samsung shipped a phone that folded in half. It weighed 276 grams, sat 17.1mm thick when closed, and ran on display technology that had never been stress-tested at consumer scale before. The category it was launching into didn’t exist, but Samsung had led enough categories to take this up with confidence. The engineering problems it was taking on had no prior solutions to reference. 7 years and 8 generations later, the Samsung Galaxy Z Fold8 weighs 201 grams and closes to 9.7mm, the world’s lightest book-style foldable smartphone, leaving behind all competitors in the foldable space. But the weight and the thinness are outcomes of something more fundamental: a company that spent 8 years solving the hardest engineering problems in smartphone design, in public, with every product, and compounding those solutions into the next one.
The Hinge Is The Part That Had to Work Before Anything Else Could
The hinge is the mechanism every other aspect of a foldable phone depends on. Get it wrong and the phone develops play over time, fails to protect the display from debris and stress, and eventually makes folding and unfolding feel mechanical rather than natural. The first Galaxy Fold’s inward-folding hinge established the format, but the Galaxy Z Fold2 in 2020 introduced the mechanism that would define the lineage: the Hideaway Hinge, built from more than 60 internal components and engineered around a dual CAM structure that allowed the phone to prop itself at various angles mid-fold. Sweeper Technology arrived alongside it, sealing the gap between the hinge and the body using precision-cut optical fibres, blocking dust and debris from entering without adding bulk. This combination turned a folding phone from a technical demonstration into something a person could actually carry.
The hinge evolved methodically from there. The Galaxy Z Fold4 changed its fundamental motion from rotary to linear, replacing interlocking gears with a mechanism that moved in a straight line, reducing the part count, cutting weight, and improving manufacturing consistency, all while maintaining the same durability standard. In 2023, the Flex Hinge on the Galaxy Z Fold5 replaced the Hideaway Hinge entirely, using four drive shafts and a dual rail structure that allowed the display to fold inward in a water-drop curve rather than at a fixed crease point. The two halves of the phone could close more evenly for the first time, eliminating the gap between them when folded that users had accepted as a characteristic of the form factor since the beginning.
The Galaxy Z Fold7 introduced what Samsung calls the Armor FlexHinge, a new structural innovation fusing advanced materials with an optimised design for both durability and compactness. The result was a folded thickness of 8.9mm and an unfolded thickness of 4.2mm, numbers that had previously been the preserve of high-end slab phones. The widened inner bezel gap on the Galaxy Z Fold8 is the kind of refinement that only emerges from years of watching real people use the phone. Samsung understood the device is noticeably easier to open one-handed, and the improvement required the same engineering discipline as everything that preceded it.
The Crease: Samsung Took 7 Years to Get to the Root of It
The display crease running down the centre of the main screen was the most discussed limitation in the Galaxy Fold’s history. Samsung attacked it across every generation with better hinge tolerances, improved bonding layers, and progressively thicker Ultra-Thin Glass, which arrived 50% thicker on the Galaxy Z Fold7 than what the Fold6 used. Each iteration made the crease less visible and less tactile, but the root cause was structural: polymer-based support films beneath the OLED panel deform microscopically under repeated folding, and that deformation accumulates over hundreds of thousands of fold cycles until a crease becomes both visible and felt under a fingertip.
The Galaxy Z Fold8 addressed this at the material level rather than through hinge geometry. Flex Titanium replaces the polymer support film with two titanium-based layers. A Titanium Alloy Film, roughly one-third the width of a human hair, sits directly beneath the OLED panel, and a laser-perforated titanium plate sits beneath that. This two-layer titanium structure resists the micro-deformation that polymer film accumulates under repeated folding, and the laser-perforated plate distributes stress differently with each fold cycle rather than concentrating it at the hinge line. The crease has not been eliminated and Samsung does not claim this, but the material physics responsible for how visible and tactile it becomes over time have fundamentally changed.
How Samsung Got the Weight Down Without Shortchanging the Phone
The first Galaxy Fold weighed 276 grams in 2019. By the Galaxy Z Fold5 in 2023, that figure had come down to 253 grams across four generations of refinement. In the two generations that followed, Galaxy Z Fold6 at 239 grams and Galaxy Z Fold7 at 215 grams, the pace accelerated. The Fold7 reached 215 grams specifically because Samsung set that as an engineering goal: the Galaxy S25 Ultra, Samsung’s own flagship slab phone at the time, weighed 218 grams, and the internal question became whether a foldable with two displays and a hinge mechanism could weigh less than a conventional flagship. The Fold7 answered that.
The Galaxy Z Fold8 reached 201 grams, 52 grams lighter than the Fold5, through a process Samsung describes in specific terms: approximately 270 components and more than 180 types of auxiliary parts were individually reviewed. Some auxiliary parts were optimised to reductions of 0.001 grams. Multiple parts were consolidated into single structures. The printed circuit board was redesigned to remove unnecessary circuits. The MFA antenna was reimagined to reduce interference and unnecessary overlap. Of the more than 180 types of auxiliary parts previously used, approximately 15 were eliminated entirely.
The critical detail is what happened to the recovered weight. Samsung recovered the grams and millimetres through materials advances, component redesign, with precision machining going back into the battery, cameras, and thermal system. The Galaxy Z Fold8 Ultra carries a 5,000mAh battery, approximately 7% more graphite heat-dissipation volume than the Galaxy Z Fold7, a 200MP main camera, and the first 50MP Ultra-Wide camera on a Galaxy Z Fold device. Getting to that battery capacity added approximately 6 grams to the device. Samsung’s engineers then found those 6 grams again through the same systematic process across the rest of the design. Weight reduction was the method, not the goal.
Samsung Mastered How To Make a Folding Phone Actually Survive
A phone with a moving hinge and a folding display faces structural vulnerabilities a slab phone never has to account for. The display flexes under mechanical stress that a fixed screen doesn’t encounter. The hinge creates a natural ingress point for dust and debris. The electrical connection between the two halves of the device is a potential failure point that doesn’t exist in a conventional design. Samsung solved the most counterintuitive of these challenges with the Galaxy Z Fold3 in 2021: IPX8 water resistance on a device with a moving hinge, the first foldable to achieve it. Sealing a mechanism that must flex thousands of times daily against water ingress, while maintaining the flexibility required for daily use, was an engineering challenge with no precedent in consumer electronics at the time.
Armor Aluminum arrived on the Fold3 as well, providing structural rigidity without the weight penalty of alternative materials. The Sweeper Technology on the hinge evolved in parallel with the device: as the hinge became slimmer across generations, the sweeper’s bristles were shortened to match, maintaining dust protection without adding profile. The Galaxy Z Fold8’s Armor Aluminum frame and Corning Gorilla Glass Ceramic 3 cover display are the cumulative result of material selection decisions refined across 8 generations, each informed by the failure modes the previous generation revealed in real-world use.
Samsung Invented Foldable Expertise Over 8 Generations
No other manufacturer has shipped 8 generations of a book-style foldable phone. The engineering knowledge embedded in the Galaxy Z Fold8, across hinge design, display materials, weight architecture, and durability, accumulated across 8 cycles of real-world use, real failure modes, and real manufacturing challenges at scale. While bulky or heavy designs on some other foldable phones created concerns among consumers, Samsung’s response was the Galaxy Z Fold8: 201 grams, 9.7mm folded, Flex Titanium display, five generations of hinge evolution in the Armor FlexHinge, and weight savings that redirected entirely into the experiences that survey cited. 8 generations didn’t just magically produce a thinner phone. Samsung mastered the category that it invented. This was achieved by understanding the consumer and constantly improving the engineering capability to build it. That’s why it’s no coincidence that Samsung continues to set the standard for foldables.
