KAIKAKU x Accu: These Screws Make Robot-powered Restaurants

Behind a one‑way mirror in Common Room - KAIKAKU’s London restaurant‑lab - a small team designs, prints and builds hardware between lunch and the evening rush. When a fixture cracks or a carriage binds, they fix it before the next tray of bowls needs to be prepared.

That pace is deliberate. It only works because the nuts, bolts and washers they depend on arrive the next day, in the exact quantities they need.

Fusion is KAIKAKU’s robot‑powered food assembly line. It’s built for pace, cost and durability. Standard parts wherever possible; custom parts only where they matter.
Accu’s role is simple: reliable fasteners, predictable quality and low‑friction procurement so KAIKAKU can ship hardware at software speed. 

Contents: 

• Fastening for FDM and food: design choices that stick.
• Building Fusion in public: from V2 to V4.
• The Friday Accu order that unlocked a launch.
• How Fusion V4 runs a service.
• People, perception and a changing kitchen.
• Made in Britain, Built in London.
• See Fusion In Action.
  
  

Fastening for FDM and food: design choices that stick.

Before the screws, the service problem.

Lunch time peaks expose the weak points in traditional food service; weighing, dispensing and the hand-on and off to staff. Queues grow fast from small slips. Space can be tight; cleaning has to be simple; product and stock swaps need to happen between lunch and the evening rush. Anything fragile or awkward to service wouldn’t last a week.

What Fusion needed to be.

Fusion, KAIKAKU's flagship creation, is a modular food service line that portions, moves and finishes bowls through to full meals, with humans stepping in where judgment adds value. Consistent in a small footprint. Easy to clean. Fast to service.

How that shaped the build.

Fusion leans on 3D printing (FDM) for housings, brackets and fixtures. Early builds used brass heat‑set inserts for threads, quick and repeatable, but with low torsional resistance and awkward to install in tight spaces. The KAIKAKU team shifted to captive DIN square nuts in printed pockets: components that resist rotation, tolerate rework and keep service simple.

“We used to use brass heat-set threaded inserts, but over time, we became frustrated with their low torsional resistance and difficulties with installation. Recently, we’ve entirely changed to captive DIN square nuts and haven’t yet looked back.” 

Ivan Tregear

CTO, KAIKAKU.

For parts that rotate around interfaces, the team favours shoulder bolts over custom shafts. Turnaround also matters: a stocked M5 shoulder bolt from Accu arrives tomorrow; a custom shaft doesn’t. 

Day‑to‑day joints use ISO countersunk and socket cap head screws (mostly M3–M5) with a preference for nyloc nuts. With around 30 motors and food being anything but smooth to move, vibration resistance is built into joint part geometries that hold preload and wedge‑lock washers (e.g, Nord‑Lock) where shocks live.

The overall outcome? faster iteration, field‑friendly swaps and fewer bespoke parts to chase.

With everything designed at their fingertips in CAD, small changes and design tweaks are almost instant. Couple that with Accu's vast component CAD model library, parts used can instantly be deposited into the design file, allowing for test fitment before ordering.

“Accu’s CAD library saves us a significant amount of time when we can’t find a model for a fastener.” 

Ivan Tregear, CTO, KAIKAKU.

Pictured: Fusion Dispensing Module. 

Building Fusion in public: from V2 to V4.

Just like software, Fusion is built iteratively.

In software, shipping early and often beats waiting for perfection. Fusion grew the same way, but in a tougher arena: a live restaurant with real guests, real-time pressures and a lunch peak that exposes any weakness in seconds. Iterative innovation here means making the smallest meaningful change, proving it under service conditions, then keeping what works and discarding what doesn’t. It’s disciplined and fast, the opposite of endless prototyping behind closed doors.

“We don’t see the point in focus groups or closed demos. We believe you’ll always receive the highest fidelity learning from real end-users and customers.” 

Ivan Tregear

CTO, KAIKAKU.

The graphic below maps that journey from V2 to V4. It shows how each version tightened flow, reduced failure points and made maintenance simpler. Rather than chasing shiny features, the team focused on factors diners and staff actually feel: reliability, speed, cleanliness and ease of use. The result isn’t a single leap; it’s a staircase with clear steps, each justified by evidence from a real shift.

• V2 was a sprint: 2.5 months from idea to demo. It served 100 bowls to investors, friends and family… then promptly gave up. Painful, but instructive!

• V3 moved into service at Common Room, London: Over 30 days it produced 3,000+ salads while mechanics, dispensing and motion were refined.

• V3B followed: a 1.5‑month redesign that fixed rough edges. Intended to last a few months, it ran daily for almost a year, operated entirely by restaurant staff.

• V4 is the step change: a broader, deeper build that spanned eight months from ideation to deployment. It handles orders end‑to‑end, not just assembly.

The Friday Accu order that unlocked a launch.

Three weeks before Fusion V4’s debut, KAIKAKU hit a hard limit: the parallel‑link bowl lift, the mechanism that raises a completed bowl from under‑counter height to a hand‑off point for staff, would never meet the throughput target required for live service.

On a Thursday afternoon, they called time on testing.
What followed? A 90‑minute whiteboard session, a 12‑hour CAD sprint and rapidly sliced 3D prints the next morning. Test-fit, adjust for tolerance and commit to the solution.

At 7pm on Friday, the team placed a full Accu order for the reworked lift: fasteners, shoulder bolts, washers and everything needed to turn the idea into a working mechanism.

By Saturday, those very components were on the workbench, ready to be installed over the next few hours. The new lift raises or lowers a bowl in about one second, removing the bottleneck and keeping launch (and lunch) on track.

“We couldn’t have moved that quickly without suppliers like Accu. Their speed and precision let us overcome this design challenge and meet our restaurant’s needs without delay.” 

Ivan Tregear, CTO, KAIKAKU.

That same bias to action shaped Fusion's software and user interface too. V4 initially shipped without a full Kitchen Display System (KDS) or payment link; orders were driven manually from the touchscreen for the first week by team members. Only after observing live service did the team add KDS, integrating where it actually helped speed up service efficiency rather than delaying for a not‑yet‑proven feature.

How Fusion V4 runs a service.

A typical lunch peak is steady rather than theatrical. Orders land, the line picks them up and staff step in where judgment helps. The goal is simple: keep the belt moving, remove stalls and make the next action obvious.

Service flow:

• Orders enter via the touchscreen or Kitchen Display System; a light scheduling software sequences salad builds so lanes stay occupied.

• Dispensers portion core ingredients; staff add hot or last‑touch items in parallel using custom gastro‑trays.

• Bowls are automatically indexed at a fixed pitch; position and weight checks keep portions repeatable.

• If a station slows, steps further down the line automatically buffer to avoid stop–start behaviour using Fusion's software.
  
  

Throughput:
A bowl advances every 10–15 seconds. Under favourable conditions, that equates to around 360 bowls/hour. Output is designed to be consistent through the peak of service rather than spiky to help smooth out service. 

The result is a predictable service rhythm: clear roles for people and machines and fewer reasons to pause the line.

“To create the best restaurant experiences through hardware, software and AI.” 

Ivan Tregear, CTO, KAIKAKU.

People, perception and a changing kitchen.

KAIKAKU is open about their use of robotics - the machines are visible - but never theatrical. 
To diners, the counter looks like a well‑organised line with some clever fixtures. The food is consistent, fairly priced and on time. That’s what matters to a lunch crowd.

For staff, the value is flow. Fusion soaks up the repetitive, time‑sensitive steps and hands back time for hospitality and exception handling. In a labour‑tight, quick‑service world, this human‑in‑the‑loop model is practical: the robot does the heavy lifting; people keep the experience personal.
It’s the spirit of cobots and the Industry 5.0 philosophy in one; technology that augments people rather than replacing them.

Safety stays tight. FDM parts are cleaned and then verified using ATP surface swab tests (a rapid check for residual organic matter) to keep bacterial counts within acceptable limits; engineers complete food‑safety training; risk assessments and PPE are standard practice. 

With all this technology and innovation, KAIKAKU have also managed to keep food standards and customer satisfaction at the forefront of every decision they have made; their customer reviews and feedback speak for themselves.

“I have been coming here for a while and I wanted to be able to give back to the business as they have been so nice and welcoming to me and with other customers too. If you are a gym goer like myself this place Is the right place to get all your nutrients and your protein. It has nice seating area, the staff are very accommodating. I have already recommended friends here and they absolutely love it, I hardly give good reviews, but I do believe this place definitely deserves it.” 

Customer review, Common Room.

Made in Britain, Built in London: Sustainable and Local.

Fusion is designed a few metres from the line it serves: most parts are 3D-printed or laser-cut in-house, with specialist fabrications handled by UK partners. That keeps lead-times short and avoids long, carbon-heavy supply chains.

“By sourcing components from Accu, we reduce the journey and carbon footprint of each fastener.” 

Ivan Tregear, CTO, KAIKAKU.

By sourcing standard fasteners and hardware from a single UK supplier (Accu), KAIKAKU cuts freight miles, avoids split deliveries and reduces packaging waste, a small but real shrink in Fusion’s footprint. Next-day availability also enables on-demand manufacturing: smaller buffer stocks, fewer “just-in-case” orders and less scrap.

Standardised fixings and modular assemblies extend service life and simplify end-of-life recovery (unbolt, reuse, recycle). When parts do fail, field-swappable modules keep equipment out of the bin and in service.

Why Accu fits this pace.

Speed and certainty make the difference between a same‑day fix and a missed service. Accu provides both: next‑day delivery as standard (and unlimited express deliveries with AccuPro), consistent quality across the range and an ordering interface built for engineers under time pressure.

One basket covers the mundane and the unusual; from DIN square nuts to Nord‑Lock washers and ultra‑low‑profile M8 bolts for tight clearances, all with CAD models to match.
Ordering is made even easier with our new Quick Order Tool, which allows makers and innovators to create a bill of materials and share their project basket with one click.

“Accu is our go‑to supplier simply because they can get fasteners to us next day, without fail. Additionally, Accu’s ordering interface is just light years ahead of other suppliers.” 

Ivan Tregear, CTO, KAIKAKU.

Want to See Fusion in action?

Fusion runs daily at Common Room; KAIKAKU’s restaurant‑lab in London. If you’re nearby, you can watch a live service and grab a tasty bowl of their fresh, nutritious salad for yourself to see the system’s flow first‑hand.

Address: Common Room -  22, Brunswick Centre, London WC1N 1AW

Maps: Google Maps

Note: The lunch peak offers the clearest view of throughput and line balance if you're looking to see Fusion in action!

FAQ's

Q: How are 3D‑printed parts fastened without heat‑set inserts?

With captive DIN square nuts in printed pockets. They resist rotation, tolerate rework and simplify assembly.

Q: Why prefer shoulder bolts to custom shafts?

Turnaround. A stocked shoulder bolt arrives next day, is easy to replace in the field and removes a machining dependency.

Q: How is vibration handled with 30 motors on one machine?

Through joint design and hardware choice: Nyloc nuts for sustained preload and Nord‑Lock where added security is required.

Q: What throughput does Fusion V4 achieve?

Bowls advance every 10–15 seconds, enabling up to 360 bowls/hour in favourable conditions.

Q: How does KAIKAKU stay fast without compromising food safety?

By combining rapid iteration with guardrails: ATP cleaning regimes for printed parts, staff food‑safety training, PPE and targeted risk assessments.

Q: How does sourcing from Accu support sustainability goals?

Consolidated, UK‑based procurement cuts shipping distance and supports local fabrication, aligning with Fusion’s Made in Britain certification. AccuPro allows for unlimited express delivery. 

Q: Why not compare to competitors' throughputs?

Performance depends heavily on layout and staffing. Fusion’s value is a consistent, repeatable throughput within a fixed footprint, making it a scalable concept in almost any setting.