I’m Vivek from India, owned a manufacturing shop. I don’t have much experience of running machine shop.
Previously I was working as a design engineer.
I’ve few doubts in mind. Let’s say I have one RFQ of CNC machining for a single quantity, it is easy task for me to calculate for single or couple of quantity by considering standard factors such as cycle time, labor wages etc.
But If I want to quote for multiple quantity, let’s say for 2, 5, 10, 100, 500 and 1000 Nos of the same part, then I misjudge quote every time and ends up in loss side or won’t get to convert quotation to order lead.
I want to make this quotation process standard, like I can set percentage at which the cost will reduce once the required quantities increased. For Eg, cost for one part is 1000 Rs. Now, for 50 part around 30 percent of 1000 Rs, hence cost will be 15000 rs for 50 Qty as per 300 Rs for single qty. , like that. ( I read this from one unknown site from US, conversion is actually in US Dollars)
I want to ask you all that is there any standard by which I can predict the cost for above mention quantities. From multiple quotation, I came to know that every time the value per piece decreases w r to some standard percentage. (Please try to answer this question w r to INR (Rs), because there is lots of different factors required to consider in other currencies)
Please answer by doubts, it will be very helpful for me and readers who has same problem as mine.
I never use % to calculate cost of quality of parts. Its all about setup time ÷ # of parts + total cycle time + metal.
Other things to consider toolong fixtures how long will cutting tools last. How long does it take to change tools out.
Material prices will very if you buy 10 cm of stock it costs a lot more than 10 m or 100m.
I hope this helps.
When I managed a job shop, I established a few things, first a shop rate for manual machining, CNC Lathe, CNC Mill, Programming and assembly. Shop rate was based on all overhead fixed costs (salaries of non-production personnel, fringes, operational costs (building, utilities, etc.), I would determine the amount of machine hours available for each machine and then divide those hours into the total fixed costs. Then when I quoted a part with multiple quantities, I would list each operations estimated cycle time and multiply the corresponding shop rate for that process. I would then add the other one time costs (setup, materials+25% and any other one time costs such as fixtures or tooling. Those total one time costs would then be divided by the multiples I was quoting and added to the machine rate number. I then added a factor such as 1.1 as my quote reward variable… This changed based on how many quotes I recieved as orders. If I was getting more than 40% of my quotes I would increase that factor, if I only got 10% I decreased the factor. That kept me from overloading my shop floor with too much work.