How will you execute this script on a regular interval? InstallOnTimer Perhaps? (Method depends on whether you host with FileMaker Server or FileMaker Pro.)
Add this relationship:
Products::ProductID = PrintJobs::ProductID
Your "print" script can be:
Set Variable [$ProductID ; value: Products::ProductID ]
Go to layout [PrintLog (PrintLog)]
Set Field [PrintLog::ProductID ; $ProductID]
Go To layout [Original layout ]
Your "robot" script can be run via robot file or InstallOnTimer to do this:
Go To Layout [PrintLog ( PrintLog )]
Enter Find Mode 
Set Field [PrintLog::PrintedStatus ; "="]
Set Error capture [on]
Perform Find 
If [Get ( FoundCount ) > 0 ]
Set Variable [$Path ; "File:" & Get ( TemporaryPath ) & "ProductPDF.PDF"]
If [ Not Isemtpy ( Products::ProductID ) //check to be sure Product record still exists]
Go To Related Record [Show only related records; From table: Products; Using layout: "ProductsPrint" (Products)]
Save Records as PDF [Restore; no dialog ; "$Path" ; Current Record]
Go to Layout [ProductsDataEntry (Products)] //container field should be on this layout
Insert File [Products::ContainerField ; $Path ]
Go To Layout [PrintLog (PrintLog)]
Set Field [PrintLog::PrintedStatus ; 1 ]
Go to Record/Request/page [next ; exit after last]
Note that I haven't set it to delete any records from PrintLog like you asked. Instead, it changes a status field in the record to keep it from being saved as PDF a second time. This allows you to review the print log to confirm what products had a PDF saved. You can modify the above script to find all PrintLog records with a status of 1 and delete them as the final steps of this script if you wish.
Note: if you are using nothing but Mac computers, you may want to use insert picture instead of insert file.
You are a GOD! I love You! :D
I will test this immediately.
Oh, and I was planing to use InstallOnTimer script.
once again Your answer has proven itself as extremely helpful! I am saying this because I had a different isue which I resolved using, not the same solution, but the same way of thinking!
I got to tell You friend, I owe You a beer or two! :)