Heat affecting accuracy

[Joe788]

Tell the boss to sit down before the contractor hands him the quote!

[rickcact]

Tell the boss to sit down before the contractor hands him the quote!

 

 

Yeah I bet it aint pretty.

[GerryS]

Rick,

 

I agree for the most part with all the comments given.

However!

As far as 0.0002" being held day in day out everywhere???

 

The dimension first has to be defined as to what kind of a dimension.

A bore? Possibly.

Overall surface? Not likely.

I hear this all the time with people stating that they hold 0.0002" on everything they cut.

Then find out they are programming to the nominal tool size of a low end tool, from a low end tool manufacturer, in a 10 year old Cat 40 collet holder.

 

Temperature stability is of extreme importance to machining accurate parts.

Even though the machine has thermal compensation software it can not account for extreme variations.

In a 10 degree variance the part alone may see more thermal change than your tolerance.

This does not even include the tool holder and tool.

 

Keep in mind also that in 5 axis certain errors actually get doubled.

 

If machines could effectively comp for real world thermals then CMMs would not need to be placed in thermally controlled areas.

 

There are things that can be done to help but one must be realistic.

 

Call me.

508-474-1133

[rickcact]

Rick,

 

I agree for the most part with all the comments given.

However!

As far as 0.0002" being held day in day out everywhere???

 

The dimension first has to be defined as to what kind of a dimension.

A bore? Possibly.

Overall surface? Not likely.

I hear this all the time with people stating that they hold 0.0002" on everything they cut.

Then find out they are programming to the nominal tool size of a low end tool, from a low end tool manufacturer, in a 10 year old Cat 40 collet holder.

 

Temperature stability is of extreme importance to machining accurate parts.

Even though the machine has thermal compensation software it can not account for extreme variations.

In a 10 degree variance the part alone may see more thermal change than your tolerance.

This does not even include the tool holder and tool.

 

Keep in mind also that in 5 axis certain errors actually get doubled.

 

If machines could effectively comp for real world thermals then CMMs would not need to be placed in thermally controlled areas.

 

There are things that can be done to help but one must be realistic.

 

Call me.

508-474-1133

 

 

I could not aggree with you more Gerry. It is tough to get it through the owners mind that each axis has its own error, along with the tool and holder also. That doesn't even include the pallet changer. It can be very challenging to say the least.

Thanks for chiming in. You will be getting a call in the next few weeks for some more advanced training, which I dont believe I have had yet.

 

Rick