The lack of good dust extraction for a table saw is a common issue to many woodworkers. The blade has huge velocities at the wood touching outside causing large centrifugal forces which hurling the dust away with high speeds. This is the reason which makes it pretty difficult to catch the saw dust.
In general it is crucial that a blade guard is used. If you don't use one, the blade has an open angel up to about 140 degree where dust can easily emit. You can easily check this out by comparing with having a blade guard on and off.
The blade guard is essential and helps a lot, but does not all the job alone.
My general approach was to catch the dust where it is created and thats at the spot where the blade touches the wood. Getting suction right at this spot is other than easy, but I managed it to get a pvc pipe just a few mm next to the blade at that position. Next step was trying to close all gaps within the saw's housing to see which impact the gaps have to suction force. Last I did a simple modification to the blade guard for attaching a second dust port. For all approaches I measured the sucked dust amount in my separator.
Watch my video above for all results. The modification with the largest improvement should be applicable to most table saws.
This mod addresses DIY people like myself who are crazy about getting the max out of their good value for money tools (doesn't mean low budget) by understanding technical coherences. If you own a $$$ table saw with a $$$ shop vac connected you won't have such issues :-).
Another modification in this context is the improvement of my karcher shop vac which can easily get modified to a high volume performance shop vac at good suction capabilities. I use it even as main sucker on the table saw's main dust outlet.
Hope you like it, I really would appreciate if you leave me a comment below or give me a thumbs up in the video above.