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Nick Eaton

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Everything posted by Nick Eaton

  1. Nick Eaton

    HST

    Hi Zoober, You are absolutely right. It is high feed machining not high speed machining. This is why I always cringe when I see the High Speed term bandied about....because the chances are its not high speed. I think this is a marketing ploy from different interests that want you to believe that there is some magic wand to move more material faster all you need to do is buy their product......what ever it may be. I would hardly call a 50T Mori with a 40 HP dual winding motor and 15000 rpm (made in 2001)a 50 tapercorncobslowmoheavy machine. Can you move 160 cubes with your machine? That was our benchmark.....if you weren't running that quick someone would want to know why....and there might well be good reasons. Sounds to me like you are more in the 60-90 cube range which is fine for a 20-25HP 40T machine. The fact of the matter is material removal rate is a function of horsepower until you get fast enough to "soften" the material. How you use the energy from your machine will depend on the HP/Spindle speed/feedrate/rigidity combination you have. And of course you want to run as high a chipload as possible in heat resistant materials (e.g. Al and Ti). And this is also helped by the larger machines......012- .015 (thats true effective chipload with thinning taken into account) chiploads are no problem, and thats with an ordinary carbide endmill.....not a feedmill. This is not to say that the big machines are the only way to get the job done. As I said there is no free lunch. They are more expensive both upfront costs and running costs. And the footprint is huge. Everything needs to be overengineered as you are moving alot of mass around quickly along with rapid accel/decel etc.....and I have seen some pretty horrific crashes.You could probably fit 4 typical 40T 3 ax machines in the same space.....then you have the 8-12 inch floor pad to pour.....the list goes on. Just as a matter of curiosity what surface footage are you running your 15-5 at. I started running 700 SFM with an airblast about 10 years ago.......it was astounding, faster and as you say way more tool life.....trying to convince people that it worked was the main problem. And I guess the orignal point was that simply running HST paths on a machine that can't take advantage of them is not going to make you faster... Cheers Nick [ 05-06-2010, 06:19 PM: Message edited by: Nick Eaton ]
  2. Nick Eaton

    HST

    Hi Carmen, Well I rough regularly at 650 ipm with or without HST. Material removal rate is not only a function of feedrate it also depends on cutter engagement. I have run .75 cutters with a 1.25 axial engagement and a 75% radial engagement at 350 ipm......do you manage that with your Makinos? Of course I had a 50T 15k spindle with 40 true horsepower. As I said the HST toolpaths ARE useful(as I said I use them all the time), but they won't turn a Haas into a Makino..... Even the more advanced products like volumil can only get you so far. If you look at the material removal rates in the region of 4 cubes/min in Ti. I have moved 15 cubes/min on a good day and 10 -13 is feet up on the couch machining. With Al its basically 4x your horsepower will be your maximum material removal rate.....without a true high speed effect going on the laws of physics and conservation of energy are somewhat stacked against you.....it takes x amount of energy to move y amount of material. So I guess it really depends on how you define "efficiency". As I said I use HST regularly on our 20k spindles because of the entries exits and transitions are designed to stop rapid direction changes putting unneccessary strain on ball screws and spindles....and these are of course good things, even on machines without a 15k+ spindle using fast feedrates. But from a strictly machining standpoint I'm not sure they are neccessarily more efficient. What spindle speeds are you running on your Makinos? If you don't have 30k spindles you are not doing true high speed machining.....you are using high speed programming techniques. As an example we once did a test(50T mori horizontal with 40HP and a 15k spindle as mentioned above). We chucked up a Dapra facemill (I can't remember if it was 3 or 4 inch). As we cranked it up and got near the 15k you could definitely start to notice the drop off in spindle load......to get a .5 inch or even a .75 endmill into this effect you have to have the extra rpms. Cheers Nick
  3. Hi Mic6 Yeah you'd think so wouldn't you?.....can't seem to find it tho'.....I'm getting a bit old now so maybe its blindness....?? Cheers Nick
  4. Nick Eaton

    HST

    What are your "normal" speeds and feeds? I always cringe a little when I see High Speed anything being "sold" in the machining industry. True "high speed" machining requires a very fast spindle (30,000 rpm minimum........yes I know you can get high speed effects with larger diameter cutters on a slower spindle....but not on say a .375 endmill....and of course we are talking Al here, there are true high speed machining of other materials but this is still pretty R&D) The idea is that you get the material so hot that it becomes semi fluid. The thermodynamics of the situation start to resemble fluid dynamics more than kinematics. The main result of this is a fall in tool pressure and cutting forces as the material starts to "flow" around the cutting edge rather than being sheared.The system does not rely so much on rigidity as the forces are reduced. Tool life is also better because of the lower impact forces and once engaged the material is not in the same sort of contact as in "normal" machining. "High Speed" toolpaths came out of this realm. It is true that they can be very useful toolpaths, I use them all the time, as they have more forgiving entries and cut strategies. But unless your machine has the rpm/horsepower/rigidity you will not neccessarily see a huge increase in efficiency (i.e. reduced cycletime). It does allow you to take cuts in material/parts for which your machine/setup is not neccessarily designed for. For instance cutting titanium on a Haas.And they are also useful when you are forced into a low rigidity situation. But you will never beat a higher horsepower more rigid machine. Unless you have a true "high speed" spindle the material removal rate of any machine is most closely a function of horsepower rather than any specific type of toolpath you might use. Some toolpaths might work better under certain circumstances but there is unlikely to be a free lunch.....somethings got to give...... Cheers Nick
  5. Hey Colin, Long time no see.....should meet at Mikie's to oggle stonkin' bod...!! I'll phone you tonight..... Cheers Nick
  6. Answered own question ....reverse main chain....bingo!! Nick
  7. Hi All, Can't seem to force the direction of the helical entry on DP. If I select climb direction the helix is cw and if conventional then ccw. I want climb with ccw helix...... Cheers Nick
  8. Sweet.....Haven't used advanced 5ax as I only use 4ax. Will keep that one in mind when its time for me to step up to the 5ax plate Cheers Nick
  9. If the inside surface is "domed" you can run a high pass and a low pass with different amounts of "lean". This would allow you to use the same geometry. Alternatly you could do two line/vectors to control each level individually. If its a dished surface its more problematic as the bottom cut will undercut your initial cut. How much is the loft? If its only a couple of thou. and you are not using 50% of your tolerance you can cheat it. Technical term is 5 axis mismatch. We see that call all the time on our paperwork in our business (aerospace). Cheers Nick
  10. You can project your vector line onto the yellow surface, you might need to untrim your surface. Then check to see if its a line or a spline. If its a spline create a point at each end and delete the spline. Then join the 2 points with a line. It can be a fair bit of work. But if it wasn't we wouldn't have Starbucks and 7-11s on every corner, we would have 5ax machine shops a thriving manufacturing export industry and a much lower deficit....!! Cheers Nick
  11. Just another thought.....you might find it easier to create 2 toolpaths, one for the "straight" section and another for the rest. You could then use lead in/out to help with the corner blends. cheers Nick
  12. The nice thing about Curve 5ax is that you can manipulate your tool control vectors to compensate; rotate around the point you create them from, project them onto the surface etc....In this case you might want to manipulte the "fanning" effect in the corners. If your vector lines change to splines during this process I create another point at the top of the spline and then redraw a line between this point and the base point. This is a bit of a cheat but if the results exceed the tolerance of the part it will have to be stitched anyway..... Cheers Nick
  13. You can construct your control vectors using create line perpendicular. I usually use the bottom edge curve. Create point segment gives me something to attach the vectors to. I like to keep everythiog on separate levels cos' it can get kind of crowded. You can use comp to surface or curve in Curve 5ax.....not sure about Swarf. If you can it will be on the geometry tab. You can also manipulate your vectors and add lean/lag....I like the amount/choices of control in this toolpath. It takes longer to set up but I usually find the effort pays off in "fine tuning" the toolpath Cheers Nick
  14. I like 5ax Curve myself as it gives me more control.....I only do 4 ax continuous tho'. Swarf is going to pose problems trying to project you drivelines properly around the surface. I have had more success with this toolpath on "open" surfaces. HTH Cheers Nick
  15. You can set up different configuration files with a "shared" computer. Go into Settings/configuration, set up MC how you want it and save the configuration as "greg's configuration". You then only need to select this file from the drop down when you start......if its not the default setting. I guess you'll have to fight over who gets this option. Remember if you are doing your verify in MC you are verifying the NCI file NOT the G-code. So it won't show dogleg rapids and a few other things which might cause problems if you are not used to spotting potential problem areas. For proper verification you need software to analyse g-code and machine dynamics, Vericut for instance.... Cheers Nick
  16. Personally I prefer NCL. Having said that if I owned my own shop I would probably not install it. It is very expensive and it is not user friendly. If you do not have a background in APT its tough. The guy who taught me APT said that only abut 3-5% of his "students" were able to master 3d and multiaxis work. 2d is fairly staghtforward........for APT. I believe the same is true with the other full engineering softwares, i.e. Unigraphics, Catia etc.....Much higher and steeper and longer learning curves. We have a local company who has been trying to hire a Unigraphics programmer for some months now......still no luck. They have also had support problems..... Market penetration is Mastercam's strong point. If you can't run the software and execute (as a company) to a high standard what's the good of a high powered system....?? And if you can't hire the people easily...... Cheers Nick
  17. You could just set it up as a sub-routine and call it 4 times with a different work offset for each face (G54, G55 etc....). Is it basically a three axis part or do you have rotations within the program? If so and you use centerline programming the above will be fine. If you use rotation macros with a different offset for each rotational view it will be more complex as you will have to construct your offsets in such a way as to give you correct output. i.e. if you have 3 offsets within the program you will need 12 for the 4 axis version Cheers Nick
  18. quote: Its flawless. Truely funny.....and it works on so many levels......get it!! Cheers Nick
  19. You could figure out a different angle to cut, but you are probably going to end up with a "fudged "result. How about cut it square and then Fillet? Cheers Nick
  20. Have to disagree with Dave....Ball Lock is a much more flexible system for a wider range of part sizes/shapes than Unilock.....which also appears to be good for parts that fit.... So it really depends on what sort of work you are doing..... Cheers Nick
  21. Great system. Used it on a twin spindle 42 pallet 50T Mori cell. Its expensive if you are going to do a hole pattern on your tombstones/beams/subplates. But if quick accurate fixture changes are what you are after I haven't come across anything to beat it. And its an investment that pretty much pays for itself on a daily basis so the costs are acceptable. Cheers Nick
  22. There are a few considerations when deciding on coolant. If you are going any faster than 500 SFM the centrifugal forces prevent coolant actually touching the tool surface at all. Carbide actually breaks down almost as fast if you run it too cool as if you run it too hot. Chipping on inserts without any dark "burning" discoloration is likely to be insuficient heat generation at the cutting edge. So for aluminium the most important function of the "coolant" is to wash chips away and prevent recirculation of the chips through the cutter. There is also a certain amount of lube action because the part is drenched in the stuff. It also provides a stable environment when everything is warmed up. You can also use an air blast to control the chips and not use coolant at all. I do all my proveouts on Al with coolant turned off and I just use the air hose to keep the chips under control. Most steels (including 15-5 SS) can be machined very well with an airblast and no coolant. Exotics and some high chromium and other alloy steels on the whole require coolant unless you are taking light radial engagement (finish) cuts. The most important thing with coolant and carbide is to make sure the coolant is completely on before cutter engagement as carbide is susseptible to thermal shock; cutter heats up and is then suddenly showered with cold coolant. This will at least cause micro-cracking and reduce tool life and worst case can cause the cutter/insert to shatter. A lot of European companies have been moving away from flood coolant due to the stricter environmental laws for some time now. Dry machining and mist coolant are widespread even with exotics. Also saves company money because they don't have to buy large quantities of coolant and they leave all the hazardous waste problems behind.....its probably only a matter of time before these practices become more widespread here. Cheers Nick
  23. Sorry I didn't get back earlier....got a problem child of my own on the machine. I would still try the short program length on the tolerance setting, have you got all the create arcs toggled?. It sounds like a fairly simple shape, so your finish shouldn't suffer. I've seen too much code actually make things worse. What's your cutter size and step over? If its .5 ball I would go with a .015 step over. I think you are generating so many triangles so close together an error is almost inevitable. To give you an idea of whats possible I have a series of complex surfaced parts. 4 setups, 750+ ops and 4 .STL libraries up to 70,000k. All on .001/.001 setting.....it was a struggle sometimes tho'..! Cheers Nick
  24. Try your tolerance settings at good surface and short program length. Just to see if this cures the verify problem......you can always return if you really need that tolerance setting. Just out of curiosity what are you making? Does it require such a fine tolerance setting? cheers Nick
  25. Thats a fairly hefty toolpath file. Have you filtered it? Nick

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