New guy with my waterblock idea

[hara]

That doesn't answer my question. I asked about TIN coating. heat resistance aside, I've noticed that TIN coated drill bits need less force to drill a hole than corresponding uncoated bits. Heat will not be a problem with coolant. There is a formula for feed rate and depth of pass taking into account RPM, material and diameter of endmill. How much does TIN coating actually help when milling. Eg: was cathars block milled with TIN coated carbide endmills or uncoated to achieve that yield?

[Balinju]

ok sorry i did not understand the question than.

I can't answer that, maybe fixittt or jaydee can or chiron

[Zymrgy]

TIN coating is going by the wayside. It was developed several years ago & the advancements in coatings has progressed tremendously. TiCN & TiALN are the new ones & the difference between TIN & those are amazing.

Coatings, no matter what they are, all strive for the same goal. Mainly to create a super hard high heat resistance & very "slick" edge to whatever cutting tool they are applied to. What they wind up doing is giving a cutting tool a longer life at higher speeds.

Take some of the cutters I run. I run a 3" dia face mill ( an insert cutter ) at about 500 RPM, .125" deep at 30 inches per minute feed rate in 4140 steel. With the TiCN insert, cutting dry ( no coolant ) I can get an insert to last a couple of hours. Uncoated, the insert is lucky to make it through 1 cut. Most roughing with these inserted cutters is done totally dry, as coolant gives a problem of thermal shock...that is when the insert is cutting, it does generate alot of heat & when it exits, if it is cooled too rapidly tiny microscopic fractures can & do occur & bye bye insert on the next pass.

Endmills are a different story, you typically always run those wet, but the wear difference between an uncoated endmill & coated are night & day. Sometimes you can see double or triple the tool life using coated VS uncoated. However, in non-ferous materials such as aluminum or copper, the coatings are not as important as in steel. This is becuase those materials are so much softer & easier to cut than steel. These materials are where the "slick" part of the coating comes in handy. At very high speeds & feeds, you can have a tendancy to have the material you are cutting stick to your cutting edge, especially in some of the softer alum alloys. I am sure you have heard some describe some fo the softer grades of copper being "gummy". A sharp coated tool will help alot in these kind of materials.

When talking about these tiny endmills it gets pretty tough. Ideally, I would run a 1mm endmill at around 30,000 or 40,000 RPM in copper or alum, but , unfortunatly, I do not have access to that kind of machines. The most I can do is 15,000. So, you run into the problem of not being able to run the endmill at high enough speeds to take full advantage of its capabilities.

Arrg...I am droning on about this shit. Basically, to sum it all up, A coated endmill will outperform an uncoated one. Longer tool life & higher speeds. TiN is outdated & I doupt that you will see it around for very much longer. TiCN is the most common by far now due to its wide range of applications.

Some basic formulas for ya all...sorry, they are in english.

SFPM(surface feet per minute) X 4...take that number & divide it by the dia of your tool=RPM

now, your SF will vary depending on the material you are cutting & what the cutter is made out of.

Steel cut with HSS ( High Speed Steel ) SF=100
Alum cut with HSS SF = 250
Steel cut with Carb = 250
Alum cut with carb = MAX ( ie how fast can your machine go )

keep in mind that there are general estimations but they are close to being what I typically run.

[utabintarbo]

Originally posted by Zymrgy
...


Some basic formulas for ya all...sorry, they are in english.

SFPM(surface feet per minute) X 4...take that number & divide it by the dia of your tool=RPM

now, your SF will vary depending on the material you are cutting & what the cutter is made out of.

Steel cut with HSS ( High Speed Steel ) SF=100
Alum cut with HSS SF = 250
Steel cut with Carb = 250
Alum cut with carb = MAX ( ie how fast can your machine go )

keep in mind that there are general estimations but they are close to being what I typically run.

Number of flutes?

[Fixittt]

ahhh that is just way to much math for my simple (Remember the KISS rule) mind.

If you dont really want to play with a calc. Then here is what you need to do. best if you are on a manual mill.

Adjust RPM, and feeds untill you get the best looking chips. Food solid chips means you are very close. If your getting dust then your RPM`s are way to high. If you are getting alot of thumping. Well you can guess.

Also something most people dont think about. Unless you are totally thrashing some material, machining should only be as loud as the motor on the machine. There will be some whining, but not much.

Of course the rules are rubber, meaning that they flew with different situations.

[hara]

What about the depth of cut? sfpm is the feed rate right?

[LiquidRulez]

Originally posted by hara
What about the depth of cut? sfpm is the feed rate right?

Depthy of cut should be no more than 1/2 the cutter diam.

[hara]

No exceptions? When not using all the diameter of the cutter you could make a deeper pass.

I find this confusing though:

Cathar's WW

As a indicator of the milling process with the 1mm mill bit on my block.

Machine RPM: 4000
Mill pass depth: 0.5mm
Feed rate: 1mm/sec (2.5"/minute)

I was surprised that the RPM was so low.

They've now milled 10 blocks with the same bit.

Why wasn't a high RPM used?

[Cathar]

The machinists have totally changed the milling parameters since then hara. They managed to knock about 25% off the total milling time.

[Zymrgy]

SFPM has nothing to do with the feedrate. SFPM is the amount of material that passes by the tool in 1 minute. Easiest way to imagine it is on a lathe. Say you have a part that is 1 foot in circumference. spin it at 100 RPM & there you go.

Feedrates are tougher to judge than speeds. Typically on a mill we use the term "Chip Load per Tooth". Now obviously a 1" endmill can handle a heavier chip load that a 3/16". What it basically comes down to is like Fixittt said, machining is done more by feel than anything else. My problem is most of the programming I do is offline, that is on a workstation using a program like mastercam so you gotta have a starting point, which is where I actually use some of the numbers & formulas I posted above.

I can say what my approx staring point will be for this block I posted above. I will be using a simmilar endmill (1mm X 4MM length...woohoo...I found some at work) to the one Cathar has used for his block.

RPM=10,000 to 12,000
Each pass will be 1/4mm deep ( .010"...I will probabally wind up pushing this deeper )
Feedrate=10 to 12 inches per minute

This usually works well for me...A light depth of cut at a higher feedrate will remove more material in less time than a heavy depth at a slower feedrate & I can guarantee that the cutter will last quite a while, however, I am not planning on mass production.

[Balinju]

Zymrgy, maybe you will find this link helpful http://www.carbidedepot.com/formulas-milling.htm

Also you could buy endmill from their web site, the only problem is that they do not ship internationally. You could look at their prices, they are quite "cheap" compaired to others I saw (especially to you ben who are buying i don't know how many).
the other problem is that they are not marked in mm, only marked in inches

[Zymrgy]

A short update....I got everything ready. I got the copper base, the Alum top all cut, waiting to be machined. I came up with the cutters I was looking for the the base...1mmX4mm coated carb e.m.. I got the things all programmed. Right now all I am waiting on is TIME. Where the machines are not mine I pretty much have to wait until they are free after hours before I can go to town. When the machine is available, I usually got something to do...( isn't summertime great?? ) I can tell you, it would never be feasable to mass produce this design. Even with cutting all the corners I could imagine I could only get the machining time on the base to 30/45 minutes. The top is no problem at under 10 minutes on the mill, (most of the time is spent on the o-ring groove....small cutters suck) but the 1/2 hour on a wire EDM would drive the price up beaucoup. The cost to produce 10 of these would probabally come in at around $100 US each. My plan is to make like 4 or 5 & then call it quits. I would keep 1 or 2 of these & give the others out in trade.....I need a pump something fierce.....still using air cooling here.

Hopefully by the end of next week I will be able to show off some pics of the base finished.

[bigben2k]

You might be interested in this pump.

[hara]

Why not program a tool stop and then cut the O ring groove with a bigger endmill. On our block (in the avatar) the O ring groove could be cut with a 4mm endmill.

[Zymrgy]

I was planning on using a smaller o-ring than that....3/32 dia ( or just over 2mm). There really is not alot of room for going much larger.

[Tacops]

How does an O-ring work?

You have the groove where the O-ring sits and then the groove where the O-ring makes pressure on right?

[Althornin]

Originally posted by Tacops
How does an O-ring work?

You have the groove where the O-ring sits and then the groove where the O-ring makes pressure on right?

nah, there is no groove on the opposing plate.

The o-ring deforms (read: squashed flat into the groove, which should be barely bigger than the total area of the o-ring, roughly) and this is what seals the block.

[hara]

Shouldn't be a problem with a proper mill, will take some time though. You needn't be anal about the standard though. You could use a 2.5mm endmill (if available) in your case. By making the groove a bit wider the O ring will last longer before needing replacement.

[Zymrgy]

A slight revision I am considering. It will add to the machining time, but not by a tremendous amount. Basically I added a bunch of drill points inside the perimeter of the fins. Adds a bit of surface area & is a easy mod. This will also bring the baseplate thickness to about 1mm at the deepest part of the hole...ie the drill point. Just wanted to see what ya all thought. The biggest problem is that it is a damn tiny drill....call it .75mm or 1/32". However, drilling copper is not anywhere near as challenging as milling it & the holes are not deep at all...... 1/2mm or .020" to the drill point.

[bigben2k]

Yep, a good addition. I thought of the same for Radius as well, but just using the same bit.

[Althornin]

Originally posted by bigben2k
Yep, a good addition. I thought of the same for Radius as well, but just using the same bit.

Is it?
If you do decide to do this, please do NOT do it at first, record some temps, then do it so we can compare.
I bet it does almost nothing, or nothing at all, for your temps.

[Balinju]

yeah a good mod, but in my opinion do not need to make dimplets to the end of the fins, i thing it is enough to make at the centre only, remember my $0.02

[bigben2k]

Worth a shot.

The dimplets really need to remain over the core area. With a thin baseplate, it should have an impact.

My original idea was to actually use a drill bit that's slightly larger than the channel, making waves in the fins. The problem is that it would require a very steady drill press, so I dropped the idea, and stuck with the dimples.

[Zymrgy]

yet another idea I wanted to throw into the mix.


Ok, what is happening here is all of those little holes line up with all of those little channels in the actual cooling block. Call it a bit of a takeoff on Cathars latest & also out of manufacturing nesisicity. One thing that I see that I am getting away from is I wanted to have a gradual taper or change from the round shape to the cross in my original design, the idea being less turbulance in this area where it is not wanted ie a smoother flow. Now, however, with this design if I want to do a one piece top ( which I really do ) I run into the problem I am trying to get away from...how much difference it will actually make is the real question. One of my reasons behind doing this change is ease of manufacturing. Getting a part into the wire EDM's ( needed for the original design ) at work is a matter of great patience & waiting...unless I want to pay to get them done. Those machines are always busy making money.

So what I got here is a flat bottomed 1/2" dia hole with that hole pattern drilled inside it.

[Balinju]

nice design, a few suggestions, why do not include a + shaped alignment of little holes in the middle of that X shape, what i would like to mean is to have the centre of the X also filled with small holes, just like the fin i suggested to add in the other design, but this time an alignment of small holes

a question, are you intending to put the jets inside the holes like cathar did in his design? that would be a good idea.
and how do you intend to design the top of this block if not the way cathar did??