U right ive point this out in an wrong way i dont mean the keys import or sweeping i mean after the import of the keys.
for ex. when i need it on an other wallet to gather funds, then should i sweep or to just send the keys to the other wallet
just the option which gains more privacy preferentially in relation to funded coins which comes from chipmixer.
If you have already
imported the keys into an Electrum wallet and you want to move the funds to another wallet... just send them in a transaction as you normally would any other transaction.
Although, you
might want to consider using the "spend from" option in Electrum, so that you avoid accidentally linking UTXOs back together by including them all as inputs to the same transaction. Also, it would be a go idea to avoid sending all the funds to the same address... as again, that creates a link between them all.
This is effectively the same thing as "sweeping"... all sweeping does is "simplify" the process for you and means you don't need to import any keys. Instead, it will take a private key (or keys) and then create a transaction that sends all available UTXOs controlled by those keys to an address of your choosing. Probably not ideal, as you can only specify ONE destination address when sweeping, and that will relink all the UTXOs back together again (unless you sweep each key individually).
So, your options are:
1. Import ChipMixer keys, then create transaction to send coins to other wallet (new keys)
or
2. Sweep ChipMixer keys directly into other wallet (new keys)
or
3. Do neither and leave the coins on the ChipMixer keys until you need to spend them
Neither importing nor sweeping is any more "private" than the other if you need to move the coins to another one of your wallets... they will both end up creating transactions that take coins from the ChipMixer addresses and send them to your addresses... and in both situations you need to take steps to prevent them all being relinked.
Leaving the coins on the ChipMixer keys until you wish to send them to someone else is probably better for privacy... but security wise is not great because ChipMixer have knowledge of the private keys and you have to trust them not to steal them (or leak the keys). So, in this case, it's a trade-off between privacy and security.
Which option is better for your particular use-case is only really something that you can determine.