I've been trying to think about how I would go about mass manufacturing a product I have in my mind. Basically, it consists of a handful of telescoping half-cylinders, about 12 inches in radius, about 18 inches long, and maybe 1/8" thick, probably made of LDPE. The issue is that each piece has a slightly smaller radius than the one it telescopes into, so injection molding is out of our budget because we would have to pay for 7 or 8 different relatively large molds.

Is there a process you might recommend for something like this? Everything I can think of would require 7 or 8 different molds (roto molding, compression forming, inj. molding, thermoforming, etc). I have a feeling the answer is no, but any ideas that allow me to not use 7 or 8 molds? 
You need to do an ROI on all candidate manufacturing processes. Consider extrusion manufacturing in your research.

what about extruding them differently, and then merging them with hot forming? but that would require 7- molds as well

It used to be that start-ups began with the “entrepreneur’s vision,” which was usually a highly product-centric idea for a company. Only much later--and after much agonizing--would the founder discover the idea itself didn’t amount to a complete business model. 

That era in start-ups is over. Or at least it should be. 

Using the Customer Development process along with the business model canvas first developed by Alexander Osterwalder, it’s possible to assemble a far more detailed version of your “vision” that includes the nine most important elements of any successful business (we’ll get to what those are below). With that in hand, you can validate your vision with the only possible “validators”--your potential customers.  As customers applaud or pan elements of the business model, you iterate the model and pivot over time based on that feedback. The constantly updated business model becomes a “scorecard” for monitoring progress as you go through the Customer Discovery phase. 

And that’s how you develop an idea based on more substantive stuff than just vision. 

9 Most Important Elements of a Business 

Osterwalder’s business canvas helps illustrate how a company intends to make money. It’s made up of nine key points that represent any company’s complete business (for much more detail, read either The Startup Owner’s Manual or Osterwalder’s Business Model Design (Wiley). 

<>Ideas for manufacturing a slightly variable part

 

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