[alexccmeister]

Hi The Blight,

I am relatively new to cnc but have learned a lot from this forum. But after saying that I am still short on my vocabulary. What do you mean by the ways? When you say 4mm screw pitch, what do you mean?

The damage motor is the one I am talking about that I can't turn the shaft. Its gone I think as there isn't any signal going to the motor. I checked the driver and it is ok. Thanks.

[tanu1029]

Hi..

If we are choosing between brass and Aluminium ..which one is better conductor of heat? I am cooling something by Thermal contact conductance using either brass or Aluminium but not sure which one to use. Any recommendations..?

Thanks

[Geof]

You can Google 'Thermal Conductivity' and probably find tables ;isting different materials. Just of the top of my head I think brass is better than aluminum but not by much. You also need to take into account the cross-sectional area and may be able to save money by using a larger cross-section of aluminum.

[691175002]

MatWeb - The Online Materials Information Resource
MatWeb - The Online Materials Information Resource

You can find the thermal conductivity of both metals on this site. I would avoid using brass for heatsinks mostly because its thermal conductivity varies greatly by alloy and is generally less than aluminium. It is also expensive and weighs a lot.

[LUCKY13]

Now copper is a differnt story, Copper is much better than aluminum. All though you do see alot of good aluminum heatsinks in computors being used. They are normally quite big when they do use it though.




Ways - this is the dove tail slides. Where the table neats the Y axis and the Y axis meats the base. Along the edge of these slides/ways you will see screws with locking nuts. These are used not only to lock the axis, but to ajust the gibs.


Gib ajustment is touchy. You want it tight enough to take out any slack, but if its to tight the axis want move good. When the slide/ways are not straight what happens is you ajust them in the middle of travel but when they get to the end it binds because it is not straight.


First you can take the gib all the way out and sand it down straight ( they are always bent). You need something flat to put the sand paper on to sand it ( like a surface plate, piece of glass, or what ever you can find). Ones the gib is flat it helps a lot. NOw the ways will not be flat either and lapping them helps. I will have to look around but there are threads that explain this lapping and how to do it. Or you can go to the CNC CookBook and BoB has it listed on his site with pictures showing how to do it.

Some people just make new gibs out of brass and this works very well on a smalll machine. It also helps with what is called stictions which is where the table acts like its is stuck when you go to move it. It takes more force to get it moving , than it does to move it after it is already moving. The better the axis works, the easier it is to get it moving.

Jess

[OptionCNC]

Copper will be your best bet for the heatsinks. displaces heat faster than aluminum.