Index Table

6 comments

dougefresh Associate Join Date: May 2013 Posts: 25	Index Table 05/06/2022 2:21 PM
	I am designing a machine that includes an indexing table. We are replacing an old pneumatic table with a servo-driven indexer. I have a Kaydon slew ring bearing that I would like to embed completely between the table top and base. This will require some extra machining, but it eliminates pinch points, which was my original intent. It also just looks a lot nicer. My manager, though, is very leery of mounting the slew ring in a pocket. I am not sure why; he did not really have a convincing argument, but nevertheless, he is opposed to the idea. Is there any reason why I should avoid embedding? I mean, it's a bearing, right? All kinds of bearings sit in housings all day long, right? Am I missing something?
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SolarEagle Guru Join Date: Mar 2007 Location: at the beach in Florida Posts: 30798 Good Answers: 1722	#1 Re: Index Table 05/06/2022 3:37 PM
	Maybe he's concerned with the lack of robust thrust characteristics, or the lack of serviceability of the bearing, or the cost, lack of stability, complexity of the design, dissimilar metals touching...one clue might be the alternative offered? Maybe there's a simpler alternative.... __________________ Break a sweat everyday doing something you enjoy
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SolarEagle Guru Join Date: Mar 2007 Location: at the beach in Florida Posts: 30798 Good Answers: 1722	#2 In reply to #1 Re: Index Table 05/06/2022 5:08 PM
	Maybe it just doesn't go far enough...? Solar tip: turn sound off... __________________ Break a sweat everyday doing something you enjoy
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SolarEagle Guru Join Date: Mar 2007 Location: at the beach in Florida Posts: 30798 Good Answers: 1722	#3 In reply to #2 Re: Index Table 05/06/2022 6:36 PM
	https://www.kaydonbearings.com/downloads/whitepapers/Kaydon-MountingSlewingWP.pdf https://www.kaydonbearings.com/downloads/catalog390/Kaydon_390_InstallMaintenance.pdf https://www.kaydonbearings.com/downloads/catalog390/Kaydon_390_TechInfo.pdf Maybe he's concerned with the trapping of heat...? __________________ Break a sweat everyday doing something you enjoy
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jhhassociates Guru Join Date: Dec 2010 Location: North West England Posts: 1166 Good Answers: 151	#4 Re: Index Table 05/07/2022 5:44 AM
	Given that you are replacing a pneumatic table I would guess that the size is not massive. Pneumatic tables have a lot more slack than a slewing ring so the surface that they are mounted on does not need to be as accurate. You may have to machine your surface even if you don't create a cavity so additional cost may not be an issue. Turning a substantial base then bolting it to your existing base is likely to be a more cost effective option. Adding an anti-pinch shroud that can quickly be removed to access lubrication points is one possibility. Maintenance may be more of an issue. Slewing rings need regular lubrication but the old oil needs somewhere to go. If you locate the ring within a cavity you have created a pocket where old oil/grease can collect and will you have to periodically strip down the machine to remove it? Industrial design is about function which includes build ability and maintenance. If the result is also "looks nicer" that is a bonus, but it is always a secondary consideration.
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jhhassociates Guru Join Date: Dec 2010 Location: North West England Posts: 1166 Good Answers: 151	#5 Re: Index Table 05/07/2022 6:02 AM
	Reinstating the new table at the same height as the original pneumatic table may be important. Not having to modify the vertical alignment of all the jigs and fixtures that interact with the index stations will considerably reduce the amount of work needed to rebuild the machine.
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dougefresh Associate Join Date: May 2013 Posts: 25	#6 Re: Index Table 05/09/2022 6:30 AM
	Thanks, all, for the replies. To shore up my original post; the base will be ground for flatness before machining, indexing speed is quite slow, and the forces acting on and against this axis are (virtually) insignificant considering the bearing's capability. It is WAY oversized for this application. Maintenance of the bearing is a great point to consider. Thanks to all who pointed that out. Access to the lubrication point will certainly need to be addressed, and I intend to look through those links on mounting. Again, many thanks.
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