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Monoblock brake caliper machining

zalectric

Plastic
Joined
Apr 17, 2015
Location
Taipei Taiwan
I am designing some brake calipers that i will machine in house (for my electric bikes which are a bit too fast for bicycles brakes and too light for motorcycle brakes).

Has any one had experience machining "monoblock" calipers. These calipers have opposing BLIND holes as shown in the photos attached. I was planning to EDM the holes but it seems like a very slow was to do it. I cant imagine a right angle head would work.

P1040883_1288838499.jpg146-1209-06-z+brembo-factory+monobloc-calipers.jpg
 
Specialty right angle milling and boring heads are used to make true monoblocks, not having seen the specific tools I suspect two of each are needed as the room available only allows one side of the caliper to be machined at a time (unless identical piston diameter and spacing is used).

And the "brcmbo" knockoff picture makes me want to vomit...
 
Specialty right angle milling and boring heads are used to make true monoblocks, not having seen the specific tools I suspect two of each are needed as the room available only allows one side of the caliper to be machined at a time (unless identical piston diameter and spacing is used).

And the "brcmbo" knockoff picture makes me want to vomit...

I suspect it's simply accessed from the slots on each end, but it's just speculation.

Calipers | Brembo - Official Website

Same engraving as on legit brembo?
 
You know they make mechanical and hydraulic disc brakes for bicycles, right? If you need more stopping power, increase the rotor diameter.
 
I am using some amazing (really nice machining) hydraulic calipers for high end mountain bikes (Hope V4/203mm rotors and some prototype 250mm rotors) but my electric bikes are more than double the weight and get up to 100kph. I can't go larger on rotors without other major design and packaging issues (I would need to make custom forks for one!).

I have look around an the only right angle heads that seem to be small enough would be the coolant powered ones. Any tips on some very shallow right angle heads? Something 3/4 inch wide?
 
That's a pretty difficult part to make, I don't know how they do it. But, I have my doubts whether there would be room to interpolate a cutter around the inside of the hole, because the bearings holding the spindle take up space and won't allow much clearance once you try to get off center with the cutter.

So I'm thinking you'd need to use a succession of tools of larger diameters to open the hole and then continue to make it larger. Maybe as many as 4 tools or more?
 
Investment cast would be my guess, tolerances can be held real close if done right.
Dan


Brembo-caliper-machining-process_02.jpg

Brembo-caliper-machining-process_03.jpg

Brembo-caliper-machining-process_04.jpg
 
The higher-end monoblock calipers are forged, and you couldn't get "seal quality" bores from an investment casting. Now, what would be interesting is to have ceramic cups placed in a mold such that the casting would turn them into the bore cavities. You'd need a small temp plug in the fluid passage of the cup so it wouldn't get filled with metal during the pouring.
 
Without having access to Brembo's right angle heads you will have to do both sides through the outside from one side like AP used to do. Monobloc calipers are much stiffer than bolt together calipers. We did some caliper flex tests at increasing pressures. Dial indicators on each side to measure flex. All in all very eye opening.
 
I am planning a trial with EDM'ed bores. I know very little about EDM machines but an old school tool and die told me "oh that's easy". Do you think this will work to EDM them with "L" shaped die holder?
 
You guys do know that Brembo has been using their "secret" proprietary method for machining those monobloc calipers for a long time now right.

Apparently it's like a secret recipe and others have been trying to copy it with not a lot of success for a long time.

To put this into perspective I am sure you know how good the Japanese are at copying and improving on someone elses new technology. Look at Japanese sport bikes. They gave up and either use Brembos or do the "bore straight through and put a big plug in it" method.

If giant Japanese motorcycle manufacturers, Honda included, with all their brain power and money haven't been able to crack this egg then it might be a whole lot harder than it looks. The fact that Brembo keeps improving upon the design and keeps the cost of just buying them from them down has kept imitations off the market since long after the patents ran out on them.

Btw, Brembo makes calipers for damn near everything. Do they maybe have one in a size you can use? Hey they race mopeds, must be using something to stop them. Just a thought.
 
You guys do know that Brembo has been using their "secret" proprietary method for machining those monobloc calipers for a long time now right.

Apparently it's like a secret recipe and others have been trying to copy it with not a lot of success for a long time.

To put this into perspective I am sure you know how good the Japanese are at copying and improving on someone elses new technology. Look at Japanese sport bikes. They gave up and either use Brembos or do the "bore straight through and put a big plug in it" method.

If giant Japanese motorcycle manufacturers, Honda included, with all their brain power and money haven't been able to crack this egg then it might be a whole lot harder than it looks. The fact that Brembo keeps improving upon the design and keeps the cost of just buying them from them down has kept imitations off the market since long after the patents ran out on them.

Btw, Brembo makes calipers for damn near everything. Do they maybe have one in a size you can use? Hey they race mopeds, must be using something to stop them. Just a thought.

We were making some brackets for a set of Brembo calipers a few years back. We had a couple dis-assembled housings to measure from. I couldn't figure out how they got in there. Extremely clean. From what I recall, there were also some grooves in the bore, for a circlip or a relief I don't remember. A small right angle head is about the only possibility
 
That part is why 3+2 machining on 5 axis machines was invented. Why are they doing 3D toolpath to make it?

Yeah, certainly makes me question how much magic there really is to it.. The WIP images were for a cycling magazine, and I suspect they're a bit of a red herring, rather than actual WIP images. They're just blocks done to show that the part comes from a solid, without actually showing the process they go through.. To the uninitiated, it would go entirely un-noticed, and to the initiated, they don't want the initiated knowing how they're doing it anyway :)
 








 
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