Why is a Hiroshima foundry making Kinnikuman products? The steel technology recognized by the author
We are Castem, a precision metal parts manufacturer in Fukuyama City, Hiroshima Prefecture!
Thank you so much to everyone who viewed our first post last time!
We will continue to do our best to share the appeal of casting, manufacturing, and our company.
Now, the star of this show is this person!!
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＞ 1/1 Scale Life-size Robin Mask ＜
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Robin Mask is a Justice Chojin who appears in the manga "Kinnikuman" and "Kinnikuman Nisei".
The mask, perfectly recreated from the original work in stainless steel and polished to a shine, weighs a whopping 7kg!
It is completely Chojin-spec.
In this post, we will introduce the behind-the-scenes story of when our new business division, "Iron Factory," took on the challenge of recreating the original work, as well as our company's precision casting technology, the "Lost Wax Process," which made the creation of such an exquisite mask possible.
Why Kinnikuman in Hiroshima?
When you step onto the floor of the "Iron Factory" on the 3rd floor of the Castem headquarters building, you are greeted by an array of impressive Kinnikuman goods. Kinnikuman and Robin Mask are there to welcome you.
We display items such as Robin Mask, Akuma Shogun, the series featuring the Devil Chojin Sunshine made with real sand from the Tottori Sand Dunes, and the 1/1 scale tag trophy held by Kinnikuman and Terryman. All of these have been supervised by the author, Yudetamago-sensei. "The real Robin is probably wearing something just like this to fight in." We even have this incredibly kind comment from Shimada-sensei about Robin Mask displayed in the office.
We also get comments from customers asking, "Why are you releasing so many Kinnikuman products?"
…Indeed.
It is neither the home of the two authors nor a sacred site.
Why Kinnikuman in Hiroshima?
Even the person behind the scenes (PR) has wondered this since joining the company.
I asked Department Manager Ikeda of the Iron Factory about the secret story behind the development!
Product development that began with a direct appeal to the author
―Please tell us the story behind the development of Robin Mask.
My boss at the time was a huge fan of Robin Mask.
I also have an older brother seven years my senior, so we had all the Kinnikuman volumes at home, and I've been reading them since I was little and loved them.
In the autumn of 2017, while I was looking at online news at home, I found an article about a T-shirt shop owner who wanted to make Kinnikuman T-shirts and made a direct appeal to the author, Yudetamago-sensei, which was granted. I thought, 'This is it!'
I immediately made a direct appeal to Shimada-senseiI told my boss after the fact (laughs). At first, I communicated with the manager, and a meeting was set up.
Behind the scenes of how Robin Mask was made
―Was it a project to make a mask from the beginning?
No, at first, various ideas came up, such asRobin Mask sake cupsand beltbuckles. There was also talk of making the Robin Mask in 1/2 scale at first, but then we decided,'No, let's go all out'. The challenge of a life-sized Robin Mask was decided.
―Were there any difficulties in production?
We struggled with making the shape faithful to the original work.We lined up various panels from the original work and designed it in CAD while looking at Robin from various angles. Mr. T, who had just joined the company at the time, worked hard on it.
―Let's ask Mr. T as well. How was this big role in your first year?
Strangely, I didn't feel any pressure.However, my boss, who loves Robin Mask, was always behind me. 'There is no mask in this world that looks like the real Robin. So let's make one!'I received that passionate thought from my boss, lined up panels of Robin from various angles, and repeated trial and error to achieve a perfect reproduction.
'That's not what the real Robin is like!', 'The angle of the visor is...' I kept moving the mouse while receiving various pieces of advice.
When I saw the completed drawing, I remember being very convinced, thinking, 'So this is what my boss was talking about!'
―So the drawings were completed with an extraordinary love for Robin.
I reread the original work and imagined over and over,'How would Robin move?' and 'From what angle do I want to show him?'While being pulled along by my boss's enthusiasm, I myself became more and more absorbed in Robin's charm...
The moment the drawing was completed, it didn't feel like just work; it felt like the culmination of everyone's'Robin love'.
―Now, here, we will introduce 'casting' and the 'lost-wax process' that made the production of Robin Mask possible.
What is the steel technology recognized by the author, 'lost-wax precision casting'?
This Robin Mask is made by pouring molten metal into a mold, a process known as casting. Among the various types of casting, it uses a method called precision casting, specifically the lost-wax casting process!
What comes to mind when you think of casting?
Frying pans and pots, automotive parts, mechanical components like gears and valves, temple bells, the Great Buddha of Nara...
Casting, which is said to have originated in Mesopotamia around 4,000 BC, is the
oldest manufacturing method in the world. It exists everywhere in our daily lives.
Also, while we use the term casting, there are many different manufacturing methods.
●Sand casting
A method where a sand mold is created, mainly using a wooden pattern, and molten metal is poured into it. It is one of the most widely used casting methods. It can handle complex shapes and large items.
●Lost-wax precision casting
A method where a ceramic coating is applied to a wax prototype, which is then dewaxed and fired to create a mold before pouring in the metal. It excels at complex 3D shapes and is suitable for small-lot, high-variety production.
●Die casting
A method where molten metal is injected into a metal mold under high pressure. Aluminum die casting is used in a wide range of fields, including automotive engine parts, transmission cases, home appliance exteriors, and aircraft structural components.
(There are also various other manufacturing methods derived from these casting techniques, such as shell molding and plaster casting.)
We have summarized the characteristics of each casting method below!
The core technology of Castem is lost-wax precision casting. Since our founding, we have continued to respond to customer requests for everything from simple shapes to difficult, complex items, with a track record of over 35,000 molds.
While meeting requests for various metal materials, we have come to handle over 70 types of steel. In addition to special steels, we also handle super-duralumin aluminum materials (A7075 optimized for original casting), which other companies do not offer, and we continue to take on the challenge of new materials.
In addition to this lost-wax precision casting, Castem also offers Digital Cast®, a proprietary technology that fuses 3D printer-based digital modeling with lost-wax casting.
Starting from just one piece is our motto, achieving mold-less and short-lead-time casting. There is no need for initial mold production costs, the selection of steel types is extremely diverse, and for parts, even a single piece during the prototype development stage is fine. Another strength is our ability to create ultra-small lot products, such as highly artistic one-of-a-kind 3D objects.
Robin Mask is a product brought to life exactly as in the original work using stainless steel (SCS13) through Castem's core technology, lost-wax precision casting. Through precise design and casting accuracy, it faithfully reproduces the profound weight and presence of the original work.
We were also particular about the structure, designing the eyes and visor to be removable. By removing the visor, you can recreate the battle against Junkman, and by removing the eyes, the battle against Atlantis—the specifications allow for the recreation of such famous scenes.
Furthermore, by using a three-part structure for the head, mouth, and visor, we pursued detail in the molding, but high-level technology is required for the precision of the assembly.
Therefore, final adjustments such as distortion correction and welding were handled manually by Section Chief R, a skilled technician within the company. Each screw required to fix the visor was carefully welded, and adjustments were made so that all parts fit perfectly.
“Correcting the distortion of the curved shapes is a quite difficult part”
Even from this single comment by Section Chief R, the depth of the craftsmanship and the value of this mask, created by pouring that skill in without reservation, are conveyed.
Through the fusion of lost-wax technology and craftsmanship that we have continued to refine since our founding, Castem's manufacturing is able to deliver products that possess “superhuman-grade” precision and beauty like the Robin Mask!
A hot topic! Appearing on Tantei! Knight Scoop!!
Thanks to everyone, this Robin Mask has been featured in numerous media outlets and online news. Among them, the appearance on “Tantei! Knight Scoop”, where Kinnikuman lover “Section Chief Robin (at the time)” and Department Manager Ikeda (Senior Chief at the time) wore the masks to perform finishing moves, had a great response thanks to their physical efforts, and 30 units were sold after the broadcast. Another 20 units were sold after the year-end rebroadcast. The Tantei Knight Scoop effect is terrifying...! (Thank you!)
Because the Robin Mask is too heavy, they went to a diver pool in Osaka. To perform the finishing move underwater, the two sank along with the masks.... “I heard about going into the pool on the day of the appearance, and I was really surprised (laughs)” they said.
※ As an aside, Department Manager Ikeda had experience appearing on Tantei! Knight Scoop during his student days for an investigation of a family heirloom hanging scroll, and he challenged the application for the Robin Mask thinking, “Since it’s a company, it might not be accepted, but let’s try it anyway!” Incidentally, the value of the hanging scroll found during his student appearance was 3,000 yen. Too bad...
New products are coming!
This Robin Mask, released in 2018, has sold over 300 units as of February this year! Despite costing 165,000 yen (tax included) per unit, we are grateful that so many fans have chosen it (TOT)
As part of the mask series, we have also produced a version with scratches that perfectly reproduces the scratches on the Robin Mask, a blue baked-paint version, and the Ashuraman mask.
(Click here for the Iron Factory EC site! https://www.ironfactory-castem.com/)
Among them, the Ashuraman mask is a super-heavyweight class with a total weight of 10kg made of metal through lost-wax precision casting. It was finished to a beautiful mirror surface by hand by Hirata Kenma Co., Ltd. in Fukuyama City, Hiroshima Prefecture, and the limited model is also treated with the patented technology “Nano Diamond Composite Plating” by I-Tec Co., Ltd. in Sabae City, Fukui Prefecture. By uniformly co-depositing nano-diamond particles, it achieves not only visual beauty but also ultra-high hardness. It is truly a masterpiece packed with “Japan Quality” that is committed to reproducing the original work.
And this autumn, a long-awaited new mask is also scheduled to be released!
Whose mask will it be and what will it look like... stay tuned!
*Once the release is decided, we will announce it on our website (https://www.castem.co.jp/) and social media (https://x.com/castem_info), so please check those as well.
Next time...
Next time, we plan to deliver the "June Foundry and Manufacturing News Summary."
Please continue to look forward to Castem's manufacturing information!
Thank you for reading this far!
See you in the next article!