Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 25th November 2008, 19:32   #16
Senior - BHPian
 
vikram_d's Avatar
 
Join Date: Jul 2006
Location: Bangalore
Posts: 2,380
Thanked: 936 Times
Default

I agree with Headers on this issue. I personally have owned 2 4-axis machines in my factory in the last 12 years. The new replacement I got for them is also 4-axis compatible but have not bought the 4-axis due to a lack of orders for such components.

Moreover from what I have seen you don't really need 4-axis machines for automobile components. 4-axis machines are generally used for turbine blades where the tool needs to move in all 4-axis simultaneously.

Also there is no real-time processing of CAD data as rightly mentioned by headers. The data that is processed comes from the CAM software. A lot of high-end CAM softwares also allow you to control the machine by sitting on the PC.

Adaptive control is available for high speed CNC machines used in the tool & die making industry where your tool is typically rotating between 12000 - 24000 rpm.

Last but not the least. Quality is not dependent on the machine. It is dependent on the Process and QC. The most important factor for quality is the moral code of the company. For eg. The 20 year jig boring machine in my factory which sits in an open shed along with all our other machinery gives much better accuracy than the same machine sitting in an air-conditioned environment in a multi billion dollar company. How do you think that is?
vikram_d is offline   Reply With Quote
Old 25th November 2008, 20:29   #17
Senior - BHPian
 
lurker's Avatar
 
Join Date: Jun 2006
Location: Tura
Posts: 1,308
Thanked: 641 Times
Default

>> I didnt get you. Fanuc is a CNC controller manufacturer. Can you elaborate on the above statement?

I meant Siemens and Fanuc, sorry for the typo.

Quote:
Its available. But the definition is very vague to me. Are you referring to the tool wear monitoring and offset correction ?
In a sense, though I am not a domain expert. Adaptive control should be important for consistency in fabrication.

the first two points that you highlighted are mainly used in the defence research, since they are often fabricating and improvizing custom parts from scratch. It may not necessarily be applicable to automative sector as such.
lurker is offline   Reply With Quote
Old 25th November 2008, 20:49   #18
Senior - BHPian
 
headers's Avatar
 
Join Date: May 2006
Location: Greater Chennai
Posts: 4,589
Thanked: 454 Times
Default

Quote:
Originally Posted by lurker View Post
>>

the first two points that you highlighted are mainly used in the defence research, since they are often fabricating and improvizing custom parts from scratch. It may not necessarily be applicable to automative sector as such.
Sir, it IS applicable to the automotive sector. I am 100% sure. I work for the industry
headers is offline   Reply With Quote
Old 25th November 2008, 20:58   #19
Senior - BHPian
 
lurker's Avatar
 
Join Date: Jun 2006
Location: Tura
Posts: 1,308
Thanked: 641 Times
Default

If you say so.

When people crib about the quality of RE Bullets being dodgy. Some of them never face any leaking problem but some units have consistent issues. If the RE guys could somehow turn to CNC for all their metal fabrication needs, which is probably what Harley does, instead of using crude jigs wouldn't it solve much of their QC problems.

there won't be any more quality and consistency issues with their products.

Quote:
I'm not sure of any realtime processing of CAD data for tool path generation.
will not the bit/head begin to deviate and lose definition over a certain period of operation. taking note of wear & tear and other factors ? In absence of realtime processing won't the learning process be 'on the job' and at the expense of the client ?

Last edited by lurker : 25th November 2008 at 21:05.
lurker is offline   Reply With Quote
Old 25th November 2008, 21:20   #20
Senior - BHPian
 
headers's Avatar
 
Join Date: May 2006
Location: Greater Chennai
Posts: 4,589
Thanked: 454 Times
Default

@ Lurker:

1. The RE bullet is a 1960s design. Also RE is not a company known for its manufacturing practises. Toyota is!

2. Yes there will be wear and tear at the tool tip and compensation is available in the machines. Also, please note that all machining / manufacturing dimensions have a tolerance, i.e. a dimension range within which the process works.

We maintain the mean dimensions to achieve World Class Quality.

Today India is also on par with the World in manufacturing and in the capabilities. The only downside of importing high end CNC machines is the cost of the machine.

HMIL, Ford, Visteon, MSIL, are a few companies that use Indian Manufacturing to their advantage and export it worldwide!

cheers
headers is offline   Reply With Quote
Old 25th November 2008, 21:47   #21
Senior - BHPian
 
lurker's Avatar
 
Join Date: Jun 2006
Location: Tura
Posts: 1,308
Thanked: 641 Times
Default

So basically situation boils down to vendor accessibility and choice.
lurker is offline   Reply With Quote
Old 25th November 2008, 21:52   #22
Senior - BHPian
 
headers's Avatar
 
Join Date: May 2006
Location: Greater Chennai
Posts: 4,589
Thanked: 454 Times
Default

No it boils down to "how the manufacturer" wants to design his process, at what cost, and at what time?

Infact, some guys go to the extent of doing FMEA on the processes.
headers is offline   Reply With Quote
Old 25th November 2008, 22:08   #23
Distinguished - BHPian
 
Mpower's Avatar
 
Join Date: Mar 2005
Location: Bangalore
Posts: 10,432
Thanked: 1,682 Times
Default

Quote:
Originally Posted by lurker View Post
the 'thud' factor is a measure of very good heavy gauge metal used plus fabricating them to very close tolerances in ultra-modern CNC facilities. This gives a strong feeling to the entire body as if being crafted of one metal block.

post WW II only Germany had such facilities and the Japs were given access to latest tech by Americans.

India was kept out of this after Pokhran by various agreements such as Wassenaar and CTBT/NPT that kept high tech CNC and plastic components out of India's reach and thus the poor quality of the earlier Indica panels as manifest.
Some of my thoughts
  • The thud comes from the stiffness of the body and the gage of the steel used
  • MErcedes cars were thudding even in the 50s and 60s
  • Body panels and doors are not made using CNC machine, they are made using stamping that are welded
  • The stampings are made using dies that are CNC machined
  • Imported dies are better than Indian. Tata can make body dies (they did for Sierra/Estate) but I believe they get them from Taiwan or somethign like that.
  • CNC machines have been available for dogs years. One of the top suppliers is Lokesh Machines but used mainly for powertrain components
Mpower is offline   Reply With Quote
Old 26th November 2008, 09:18   #24
Senior - BHPian
 
ananthkamath's Avatar
 
Join Date: Jul 2005
Location: USA
Posts: 1,194
Thanked: 46 Times
Default

Quote:
Originally Posted by lurker View Post
If the RE guys could somehow turn to CNC for all their metal fabrication needs, which is probably what Harley does, instead of using crude jigs wouldn't it solve much of their QC problems.

there won't be any more quality and consistency issues with their products.
Not to be an ***, but computer control is primarily used in machining, although there are some fabrication-related machines controlled by CNC.

Quality and consistency has nothing to do with CNC, it is only an enabler. Quality comes from good practices and a dedicated workforce.

And I agree with the others, I worked as quality engineer for TVS Motor, first in fuel tank fabrication, then in frame welding, then in machine shop, I can assure you that there are some CNC machines in there that are older than 25 years now. You would be hard pressed to find a manual lathe or bridgeport-style mill in the entire production facility. This is true of most suppliers except the smallest ones as well.

Your 5 axis argument does not hold any water either, I have personally seen 5 axis machines which have all the features you mention except maybe adaptive control, mainly because said machine was not used for production but for prototyping. I have seen adaptive control as well, it was a Marposs (I think) gauging system used in a crankshaft grinder.

Last edited by ananthkamath : 26th November 2008 at 09:23.
ananthkamath is offline   Reply With Quote
Old 26th November 2008, 12:11   #25
Senior - BHPian
 
vikram_d's Avatar
 
Join Date: Jul 2006
Location: Bangalore
Posts: 2,380
Thanked: 936 Times
Default

Quote:
Originally Posted by headers View Post
No it boils down to "how the manufacturer" wants to design his process, at what cost, and at what time?
Quote:
Originally Posted by ananthkamath View Post
Quality comes from good practices and a dedicated workforce.
I totally agree with this and cannot emphasize on this point enough. You can make the best of components on the crappiest of machines if you have good processes and workforce in place. You can also make the crappiest of components on the best of CNC machines without any processes.

Haven't you heard "a bad workman always blames his tools".

Last edited by vikram_d : 26th November 2008 at 12:13.
vikram_d is offline   Reply With Quote
Old 26th November 2008, 12:37   #26
Senior - BHPian
 
srishiva's Avatar
 
Join Date: Nov 2006
Location: Bengaluru
Posts: 3,580
Thanked: 823 Times
Default

A while ago there was a study on how the Japanese could build better cars in the U.S while the U.S companies could not using the same vendors in the U.S.
The difference was in the design, process and specifications that are handed out to the vendors.
srishiva is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Volvo-Eicher open Tech Center in Mohali, offering automotive training programs GTO Commercial Vehicles 6 27th July 2011 21:53
Capability of 5-axis CNC. Mind boggling vijaycool Shifting gears 5 6th November 2009 12:53
A Story of two guys and two high revving machines GTO Street Experiences 11 13th December 2005 10:28


All times are GMT +5.5. The time now is 22:14.

Copyright ©2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks