Inside The Factory – Mizuno Pro 241 / 243 / 245

On the dawn of the launch of the Mizuno Pro 241/243/245 irons, Director of R&D David Llewellyn takes us closer than ever to Mizuno’s renowned Grain Flow Forging plant – to discover how far the process has evolved in recent years. Mizuno has produced its forged irons in Hiroshima, Japan, since 1968. More info at MizunoGolf.com on Monday 8th January from 2pm UK time.

Most people when you think of a forged Golf Club what comes to mind is is getting the form of the club head through pounding people might think that it’s not a very precise process the way we do things here is it’s extremely precise and the final shape is basically the final

Shape this is where it all starts these are the raw materials they actually start off as an Ingot a very large Ingot and then these are extruded into their rod form and that’s kind of where the grain flow starts uh as it goes through the Extrusion process those grains are

Being fed through the extruder and they start to align and that’s going to be very important throughout the process how we accentuate that grain flow 241 uses the material that uh I would say we’ve been using the longest which is our 1025 m carbon steel it is an elite

Version of that material and we call it Elite because of the very very tight tolerances we have in terms of what goes into making a mild carbon steel so we can have a very consistent material whether it’s from set to set or head-to head within a set it’s all very very

Consistent because of the that Elite status of the material the Muno pro 243 which is our high performance shallow cavity back iron the the material Choice there really is more about the material properties itself we’re looking for high strength but we’re also looking for a material that has enough elongation that

We can forge an entire head out of it the material has to have the property where it can spread out uh throughout the mold and be able to uh form an entire head so that’s why we use the 4120 material which has a little bit less carbon in it than the material that

We use for the uh 245 model which is the 4135 the higher the carbon the more difficult it is for it to spread out on the mold but the stronger it is but Tomo don’t they use uh different diameter for different clubs within uh within the set

Yeah they can optimize the meat flow by changing changing the diameters so smaller diameter for long iron mid uh larger diameter for short irons pitching wedes once these are C cut into billets they’re going to be sand blasted perfectly clean and as they go into the primary forging process they’re actually

Heated up to uh 1200° C where uh any other kind of impurities are just going to uh melt right off and just to just to kind of give everybody a sense for uh how many heads we’re looking at here uh each Rod can produce uh approximately 50

Golf Club heads and these come in bundles of 80 I believe so each each one of these bundles you’re looking at roughly 4,000 Golf Club heads inside the factory here they can make about 4 to 5,000 heads per day this is the tooling room and here at choyo they actually have four dedicated

Uh CNC Mach for making moldes how many moles it takes for one set of irons it could be as many as 30 right so that’s a lot of CNC time these machines are running continuously and that’s something in product development that we have to be very cognizant of is how many

Forge models can we actually create the tooling for some people are curious about you know how many how many heads can come off of one mole and the average number of heads is typically around 4 4 to 5,000 heads uh and that includes uh uh refreshing the mold every thousand or

So hits uh to make make sure that the the geometry is exact make sure every radius is exact uh making sure that the final product is exactly what we want it to be uh there is a there is a tooling light what we’re looking at right here

Is the Muno pro 243 7 iron EDM tooling and over here you’ve got the CNC machines and they’re making the tooling the molds uh for the overall head uh in the case of EDM the reason why we use that we use it for the score lines so we

Want to be able to within our Precision forging process stamp or press the score lines into the head which means we need extremely tight tolerances in terms of the geometry of the score lines right there’s rules that govern the score line geometry and we want to be able to go up

To the level where we have the appropriate amount of spin but make sure that nothing illegal is going to happen so that’s why the EDM process is used for creating the score lines on the tooling using this machine right Here what we’re what we’re seeing here actually what we’re feeling too you can feel it on the ground you can feel the vibrations when this press is hitting feel it on the ground right here is the primary forging process it’s a it’s the same process we were all model whether

It is the 241 the 243 or the 245 what you’re looking at is a 3/4 ton airhammer press they call it air hammer press because it’s pneumatically controlled the Craftsman who’s operating the machine right now is actually using a foot pedal to control the height of the hammer press

The first thing he does when he grabs that glowing hot villet is he puts a bin into it and then there’s three more shots of the hammer press each shot the H the the material is spreading out more and more into the hole so we’re working the material we’re working the material

And and allowing those grains to flow into place as it’s being hammered those three TI okay so now we’re looking at it from a little bit different angle you can see a little more uh what the Craftsman’s doing and this is actually a very skilled position uh it’s a it’s a it’s a

Long training program of about 3 years before the Craftsman’s able to actually work the prep as he’s working the Press you can see a little bit more from this angle uh how he’s working the foot pedal to raise up that hammer press to a certain height and he’s watching to make

Sure that the material is filling the mold and very uniformly to ensure that grain flow very similar process is exact same process for all three models the 241 the 23 243 and the 245 really really just feel it when that hammer press HPS the vibration in your body was it with such Force

I think this is uh pretty interesting here because this is what the Craftsman’s looking at these are actually starting with the Billet goes through this machine for the stretching and then the first shot here is bending it having placing the mass where we need it and again controlling that grain and

Then these are the three shots that you saw on that primary forging machine bang bang bang and you can see here this flash material hasn’t fully formed wared yet so it still needs to flow more so on the second hit more flash meat comes out here and then finally on the third shot

Now the flash meat is complete and what you’ll notice is that there’s limited flash meat here and that’s when that that is actually part of our grain flow Forge HD where we actually block some of the flash here so that we can capture a higher density of grains on the club

Head right there behind impact to enhance the feel further and then over here you’ll see uh after the flat what what what we call the flat cut it’s basically like a cookie cutter and we can look at that over there in a in a moment but basically it’s cut from The Flash and

The head drops out like that and then this is this goes off to be Recycled okay so what you’re seeing here here is The Flash cutting process so after the head comes off the primary forging mold it has all this extra meat around it right so as it’s spreading out on the mold what the engineers are looking for in this flash meet when they

Analyze it uh they could tell a little bit about the head based on how that material flowed into the flash so if we have a nice uniform flash meat around the head we know that we’ve captured the maximum number of grains within the head you can see the process itself is kind

Of like a cookie cutter where the head with the flash around it is placed on the tooling and then the Press comes down and basically pops the head out and then the flash meat is thrown in this bin here where it goes to recycle and the head goes down on a conveyor belt

Where it lands in another bin where it can cool to air temperature when we were looking at the primary forging for all these models 2 1 243 245 the process was very similar but after we moved over here to the pre Precision for Gene building that’s when

They start to diverge a little bit basically they’re same but once you start talking about different materials like the 4120 prali there are some differences at this stage uh number one as you’re looking at here the heads are being fed into the preheat furnace the temperature is a little bit higher than

It is for the 1025e mild carbon steel because of the properties of the material in order for that material to flow it has to be at a little bit more elevated temperature so if we go around there we can also see another difference again this is where the process diverges slightly for of

Biocarbon Steel versus chromal what we’re seeing here is the Precision forging process of the mauno pro 243 and you can see the Craftsman here is taking it from the furnace here at a more elevated temperature placing it on the mold and then the Press come hydraulic press comes down squeezes it and then

You can see a spray quench so it’s shooting water at the face of the iron to cool that part of the iron head down very quickly locking in that grain structure on the the impact surface of the club head to make it stronger so it can lock it in permanently we want the

Face to be very strong but we still want the hosle to have a certain degree of malleability so for adjusting LOF and L angle so we’re getting the properties of the material that we want based on this process the spray quinch the temperature and the property of the

Materials we’re now on the back side of the Precision forging press here and you can see uh on the shoot right here the two missa pro 243 heads after they’re forged they come down this shoot and come around here on this conveyor belt and they they sit here as they uh cool

Down to air temperature the last step before we’ll go into the quality control room is we got to clean the heads up so when they come out of the off the forging press they have some oxide on the surface maybe a little bit of scale on the

Surface and what the operator is doing here he he’s loading heads onto these trees here and then once it’s fully loaded that this chamber is going to close and then it’s going to get sand blasted like the the head is going to get sand blasted and it’s going to come out looking very

Much like this it’s going to be it’s going to be perfectly clean all the oxide’s gone and it’s now ready to go to Quality Control this is quite a bit different than the uh flash cut after the primary forging the heads are cooled down the heads are uh clean and very controlled process

Just taking that last little bit of flash that was created during the Precision forging process so you can see that there was a lot less Flash than there was after after the primary forging so there was not that much flow of material going through this but there was very much the tightening and

Elongating of the grains as they’re going through the Precision forging which just a little bit of flash meat Much cooler in here okay so here’s the mauno pro 243 this is this model is probably where we push the technology the most you can see this little recess area right here that is the thinnest that we’ve ever gone uh in in our forging process close

To 2 mm and then we come back and put the micro slot in so that we’ll we’ll really have the the the thinnest face that we’ve ever had in a one piece grain flow forged head so and and that’s the 4 through 7 which is the Chromo material

Of course the eight through gap wedge or the 1025e but um really challenged and you know of course our our partners here at choyo they they they push the limits of the technology in terms of how thin we can go on the face thinner the face get

More energy to the golf ball higher Co increased ball speed deeper center of gravity uh EAS ease of launching the ball so I I would say that the 243 is is is definitely where we push the most on this cycle yeah I have come here like over 10 20

Times but every single time when I visit here I am impressed actually because of the new material and new process of for M Pro 241 243 345 this time is actually I impressed even more than before yeah what we’ve seen today from the primary forging to the various uh Precision

Forging how that turns into such a precise final drop uh never ceases to amaze me and the new Muno Pro 241 243 245 um just taking those processes and uh particularly in the case of the 243 and 245 just kind of pushing them to the

Limit uh in terms of what we can do to to find performance increases and and that that’s that’s what’s impressed me the most is just how it happens and and just we continue to push continue to push