under the payment terms of D/P,  buyer pay the money to bank, then, Bank give you B/L of goods, you can take back goods from shipping company.if you never receive our press brake, you can sue and accuse your bank.  so, do you have risk?  why not believe in your bank?

Under the payment terms of D/A.   you will receive the sheet metal brake as long as you promise to pay by word of mouth.so, you must have high credit in your bank. that is to say that your bank must believe in you.if you can not pay as your promised , the bank will sue you and freeze your money.

Please search in the google for more understanding about D/P and D/A