Die cast aluminum vs CNC aluminum

[billystrikero]

Does anyone know if there exist advantages and disadvantages between a die cast aluminum reel frame vs one machined?  Is there a difference in metallurgy?  And how about chemical difference from being casted?

[ReelSpeed]

The biggest difference I would say, in regards to fishing reels, is the crack sensitivity or brittleness of cast vs forged/machined.  The grain structure on cast aluminum is not nearly as tight as on forged aluminum and many times this leads to stress failure.  How many forged/machined aluminum frames have you seen broken at the reel seat?  That is usually the main point of stress and just like the graphite frames, the cast aluminum frames can be prone to failure.  A lot also has to do with the post cast processing..if there is any.  Anyway, you may use a cast aluminum frame for years and never have a failure... but it is good to be aware of the difference and fish the reel accordingly.

my $.02

[JGB]

With my limited experience with machining many types of aluminum, stainless, brass and plastics over the last 20 years I have come to appreciate a quality chunk of metal and the qualities of that metal that give challenge to transforming it into a piece of mechanical perfection.

Die cast aluminum is less dense than forged aluminum. This is partly due to gasses that remain trapped in the casting. The grain or aluminum crystals in die cast are randomly arranged and tend to be short rather than stretched out like in forged aluminum. When machined die cast produces small brittle flakes not unlike coarse sand. Forged aluminum when machined produces continuous smooth strips that keeps it's original strengths.

For fishing reels forged is a better choice for heavy duty applications with tight tolerances. If you want light weight and low cost die cast is good as long as the frames are not heavily loaded and the surfaces are passivated and sealed (painted or powder coated)to prevent corrosion. The fishing industry has come a long ways with die casting and have  been producing die cast frames with higher strength and more density. This involves controlled cooling and casting in low pressure gasses that prevent or reduce trapped oxygen. I use some die cast reels from Daiwa (Saltist 20 II speeds) and they seem to have low gas content and high purity. I just need to be OK with that if I drop one on concrete the frame may crack. A forged reel will dent or bend before it fails.

Trapped gasses form microscopic pockets and can get grouped in bunches that make the aluminum weaker (kind of like perforated paper). In extreme cases the cast aluminum can actually be porous. In the casting process the molten aluminum is injected into a die mold and than allowed to cool. During this process the aluminum shrinks and can and will form stress points and micro cracks. The forging process forces out the gasses and cracks and fuses the grain as well as work hardens the aluminum .

Die Cast:
light with low production cost (after tooling)
Poor tension strength due to pockets, cracks and non aligned grain
Does not tolerate bending (brittle)
Cracks and voids allow entry points for corrosion to start.
Very easy to machine, drill and tap
Poor strength and high levels of impurities that add to the weakness.

Forged:
Dense and costly to machine
Malleable
Bendable
high strength
Machinable
Work hardened and can be heat treated.
Can be anodized.

Jim N.

[billystrikero]

Thank you gentlemen for your response.  The follow up question would be whether the reel manufacturer would take the differences in die-casting and forging into account and concoct a different aluminum alloy recipe to compensate and up to the point of comparable price performance. 

Furthermore, is forging another form of die-casting but under pressure?  Can it be assumed that reels in the low and mid hundreds are forged rather than machined from an ordinary aluminum alloy block and possibly heat-treated or anodized?

The new machined reels are lighter than their die-cast counterpart, and the likelihood of them being made out of forged aluminum seems slim because forging compresses the metal, making it more dense and therefore heavier than casting.

[CapeFish]

what probably happens is that you can get away with less material if you use forged aluminium, hence less weight even though it is denser than cast aluminium. look at the dramatic reduction in frame size on the new Trinidad A reels compared to a similar sized Torium

[ReelSpeed]

The casting vs. forging is just a price thing for the manufacturers.. They really cannot take one process into account to make it better.  You will almost never see a cast frame reel that has the durability(stretch) of the forged reel.

The usually very easy way to know is the anodizing vs. coating.. you cannot anodize cast aluminum, so they are always coated or painted or something like that.. all the reels that are anodized, are machined/manufactured from standard aluminum stock.

Likely the most ultra light reels in aluminum are made out of forged stock because if it were cast, it would probably break very quickly and they need the toughness of non-cast stock.  You definitely can make a thinner wall reel with forged stock while still retaining the strength. 

Aaron

[billystrikero]

Now that we have established the fact that anodized reels are most likely milled from standard aluminum stock.  Is it safe to say that they are inferior in longevity and durability than the other manufacturing process (die-cast or forging)?  There are so many types of aluminum alloys to utilize for the fishing.  For example, there are the 2000 series, 3000, 4000, 5000, 6000, and finally 7000.  Each digit denotes a specific percentage of metal.  Then, there is the heat treatment and chemical anodizing to strengthen the alloy.  The eventual question is whether the additional processes contribute significantly to the total cost where it is comparable to a die-cast or forged version.

Since there are so types of aluminum compositions, could a die-cast reel have a different metal composition than its forged counterpart to account for its brittleness?  Being that the metal is not as dense as forging, the frame may be more bulky and most likely heavier but just as strong as forging for the specified fishing capacity.

[ReelSpeed]

Anodized reels are always from aluminum stock.. you cannot anodize cast aluminum.

Forged/barstock aluminum is not inferior to cast and probably never will be.. at least in regards to fishing reel frames. I can bang on a forged frame with a hammer and watch it bend... try that with a cast frame and it will crack or shatter.

There are not a bunch of types of barstock aluminum to use for fishing.. first, only certain alloys will anodize correctly and have correct strength and durability. But beyond all that, there are only two that are used in the marine environment!  5000 series & 6000 series.  this is why everyone will probably use 6061-T6 to make reels from.  It is one of the cheapest aluminum alloys available and it is good for marine. Although the cheap factor will probably trump everything for today's manufacturers.  All your boats are made from 6061 or 5086.

Heat treatment is done to the material before it is even bought to make the reel (6061-T6 Bar stock) and doesn't add to the cost.. Anodizing does add to the cost but it is soo cheap that it really doesn't!  It would be a wash to compare the coating of a cast aluminum verses the anodizing of bar stock aluminum.. if anything it probably cost more!

So in summary, it is all about the process.. I can make machined reels in smaller quantities waaayyy cheaper from bar stock than to develop a casting process.. If I was a large manufacturer making 100 of thousands of reels, then it makes sense to cut costs and look at casting as an alternative...if I need a reel at a lower price point. 

[wallacewt]

hey billystrikero,if you can stump the alan tani experts you win a $1,000,000.

[billystrikero]

We have established the order of strength and durability: 1) forged aluminum being the best, 2) die-cast, and 3) milled aluminum.  Let's eliminate proprietary die-cast and forging manufacturing know-how created by niche players and refer these two methods as generic liquid-cooled metal as die-cast and compressed liquid-cooled metal as forging. 

The two factors left to intervene would be the metal composition of the reel frame and the size of the frame, being a larger and thicker frame for heavier fish species. 

While a few people have stated that die-cast is inferior to forging because it is not as dense and so forth, can we not shot-peen a die-cast frame and mill it?  Would it not be as strong if not stronger than forging? 

Milled aluminum is not discounted in any way.  While the general fishing community is only exposed to the 5000 and 6000 series aluminum, are those the only metals viable? 

In my limited knowledge, the fishing reel is among many inventions that express man's true ingenuity.  No electrical or petroleum propelled propulsion to assist in the hunting of man-size fish or larger using an arm-crank 3 pound gear.  That is true genius!

[ReelSpeed]

Sorry to confuse with some of the terminology.. but forged and milled aluminum are essentially the same.  As far as aluminum goes, if a manufacturer is not using a casting process, then it will be made out of round bar stock some other available stock.  I just called it forged as in, not cast.  So I will say the real order is 1.) milled aluminum 2.) cast aluminum.

You cannot mill cast aluminum to get the same properties as milled bar stock.  Milling the aluminum does not change the grain structure and that is the main thing in play here.  Same a shot-peening.. does not change the grain structure.. might make the outside harder, but also more brittle..not good.

Yes 5000 & 6000 series aluminum is all that should be used.  They are the correct alloys for a marine/water environment and you would not benefit anything going to a different alloy.

Again, it is always a mix of cost and use.  You could technically make a reel frame out of 2000 series aluminum, but it would not be very corrosion resistant with an anodize finish as well as costing more money.. so now you need to powder coat or something.. again more expensive. so you end up have a more expensive material, with a more expensive coating that really offers nothing in return.  There is no reason to change from the standard 6061 aluminum frames, because they are not structurally failing!  This is why companies will keep trying to make frames and parts thinner and thinner. 

Usually you come up with a better moustrap because the current one does not work that great.  6061 works great as it is and it is the cheapest option in bar stock.

If I was going to look at improving something, it would be the coating.  I am actually working on that right now with one of my customers.  Anodizing is good, but it isn't perfect.  Powder coating is nice, but can chip away, which looks terrible and will sometimes fade with UV exposure.

[billystrikero]

Mr. Reelspeed.  There are at least three methods of manufacturing a fishing reel: 1) Forging – compressing metal when it is either a) hot while being die-casted or b) cold when the cast is at room temperature.  2) Second methodology is die casting, look at the Shimano Tyrnos.  3) Thirdly, milled aluminum bar stock is another alternative to creating a fishing reel frame.

Example of each technology from their respective websites:

1)   Forging: Shimano Trinidad A.  You will find words "cold forged and machined"
2)   Die-cast: Shimano Tyrnos.  Milled die-cast: look at the frame on the Penn International 975CS and tell me that my observation is incorrect because I feel cheated.
3)   Milled aluminum: Daiwa Saltiga.  You will find repeated reference to "aircraft grade bar stock" being machined/milled. No mention of forging.

As for the two aluminum series, 5000 and 6000, they are very cost effective.  Try the 7000 series; there are specific grades with respective heat treatment and are marine grade. 

[ReelSpeed]

This is a subject that seems destined to failure in a forum.. better over a phone or something.

Yes, there is a forged aluminum, there just is really not much difference in the milled aluminum properties and the forged aluminum properties as it relates to a fishing reel.  Usually one process serves the fishing reel design and manufacturing process better than the other.  A reel made out of bar stock is almost identical to a reel that has been forged. You have to not go off what a manufacture says as there is marketing involved.  Let me break this down.

Milling is just a machining process.. that is all. You can have forged, milled aluminum.  Just as if I drilled a hole in a aluminum plate and called it drilled aluminum.  Just a process, does nothing to the properties of the metal.

If a Trinidad A is cold forged, then they use a machine to press the aluminum into the frame shape and then have a cnc mill finish off the rest of the fine details.  Probably just to get a certain frame profile.
If a Daiwa Saltiga is milled from bar stock, then they just start with a piece of round material and have the cnc mill make the entire frame.   

Bar stock is already a form of cold forged aluminum.  To make bar stock you have to extrude a larger diameter aluminum rod down to a smaller diameter aluminum rod.  This is a process of forging.. although the process is normally referred to as extruding or drawing. 

As to your die-cast 975.. your observation is incorrect because that reel is made from milled barstock.. not die-cast.  The inside of those look cast because they are a little rough, but that is just an unfinished surface after forging.

Your Shimano Tyrnos is die-cast...period.

Again.. 5000 and 6000 are THE aluminum to use in water.  someone may be able to alloy 7000 series to work.. but you gain nothing in regards to a fishing reel!  Again, every major aluminum saltwater fishing boat that is built today, is built with 5086 aluminum because it resists saltwater corrosion the most.  The downside to 5000 series is that it is not heat treatable and has to be cold worked to get its strength.  This is why 6061 is what they will continue to use in fishing reels.  You can heat treat to the temper that you want, it is good in saltwater and it is cheap.

Aaron

I will also include.. many times a company will use the casting process because it can produce shapes and profiles that are very difficult to forge or machine.  and it can do it with very high repeatability. 

[billystrikero]

I thank everyone for his contribution because I know what to look for when purchasing my upgrade. I would like to include this link for reference: http://www.trinityforge.com/why.html.  The opening sentence is critical when deciding between Shimano or Daiwa or whatever reel out there.

[JGB]

FYI on working on die cast reels:

Die cast frames metal is not very malleable and screw threads can and will shear (stripping) more easily that in a milled forged frame. Of bigger concern is when a cast frame reel that is lightened  it is very easy to crack the frame when replacing a screw where too much grease is in the hole. Alan has told me of experiences where screwing a greased screw hole and there is a light ping and a cracked frame. Moral is on cast frames only lightly grease the screws not the hole. The sad part is this is more of a issue on high end reels where the screw thread tolerances are very tight. cheaper reels usually have more slop and gives the grease a way out.

Jim N.