Drafting and 3d printing, do I need iso certificate for my company

Welcome! We cannot answer this question. You will have to do some research into discovering the answers to the following:

1. Do any customers require or prefer your organization to be ISO 9001 certified?
2. Are any of your competitors ISO 9001 certified?
3. Do you miss opportunities to bid on work because you don't have an ISO 9001 certificate?

How big is your company in terms of employees? There is a lower limit at which it becomes a cost to maintain a certificate which you have to justify in terms of additional sales revenue because you have the certificate. In other words, it costs (let's say) $X,000 to be certified, how will it be paid for by extra business being awarded to you, from any profit margin.