Laundry detergents are actually a mixture of a detergent and a vegetable gum that traps dirt and prevents it from being redeposited on the clothes. Unless you have millions of tens of millions of dollars to invest you will be buying your feed materials. The machinery to mix the detergent and press it into cakes is available off the shelf and would probably cost in the half million to one and a half million dollar range. I should tell you that this idea has been tried before and was not a success.