For hobbyists, you go to a store to buy products. The prices for these products are all clearly listed in the store catalog, and you can easily search for parts by lowest price or read customer reviews of the products.

For industrial engineers building complex machines, how do they buy components? Or don't they worry about cost, and leave it to their employer to eat the cost as a part of doing their line of work?

Is it possible to "shop around" for low-cost engineering components?


It is unclear to me how someone building a robot on their own as a small one-man startup can make the step from the world of toy robots, to larger and more industrial robotic components.

Most of the non-hobbyist stuff is hidden away and not exposed to the world. While a product catalog might be available, there are no prices listed for anything.

For larger industrial components, there does not seem to be any realistic way to shop around for the lowest price or best value, since pricing for much of the big stuff is basically unavailable.


For me personally, I am interested in trying to build my own powered exoskeleton on a middle class American income, so I can't afford to be paying 1000 bucks for a single electrohydraulic proportioning servo valve, when I'll need probably 50 of them. But shopping around for low cost ones is basically impossible as far as I can determine, because pricing info is generally not available or searchable from the majority of manufacturers.


3 Answers 3


For an industrial setting funds are not unlimited but the value of the machine to the process is known or predicted and if the benefit is greater than the cost, the funds are sought.

Relationships with suppliers are built up over time. A lot of these relationships are old, passed from one team member to the next. Typically one maintains a relationship with multiple suppliers of similar capabilities to reduce the risk if something happens to any one supplier. So you intentionally buy product that you know will be more expensive or lower quality to keep the relationship established.

You will have to work to find suppliers and build those relationships.

You are also working with prototype quantities which adds another challenge into the mix. Some suppliers (whether it's machinists or components vendors) don't like to waste time with small fish. It's not worth the effort and there is a higher risk to them of not getting paid. That's kind of the way it is.

I've worked in robotics prototyping for a long time, for both institutions and small but well known companies. Working with prototyping quantities (2-20) has always been a tough sell. You start to get a feel for whether the supplier will work with you pretty quickly.

That said, if you do your leg work you can find everything you need. For instance, I needed a custom bearing made and the big guys laughed at me because I needed less than 100,000. But I called around and got lucky, finding the small shop that did prototypes for the SKF research team. On the other hand, I needed A custom gear+shaft and one of the big companies that normally does stuff for helicopters slotted the design right in with no problem. You never know. You just gotta pick up the phone. A lot.

Regarding costs it's unclear whether this is a personal project or a startup one. If its a startup, try pitching your design to investors or directly to your market. Even if you want to self fund this serves as a good test, if neither are breaking out their wallets, this should be a big warning to you that the world is not ready for your idea. I've had several friends, with PhD's in robotics from good universities, throw a way a lot of money on failed startups that did not meet this test.

If it's a personal project you may have to resort to dumpster diving and other similar techniques. Bosch may want 5K for their light weight high performance valves, but the Ferrari racing team (or whomever is near you) is probably throwing out some because they have 10 hours of use and the driver is complaining.

The phone is your friend for the industrial components and services world. You'll get a faster response than email. It may help for you to throw up a 1-3 page website for your company (make one up if you don't have one, a sole proprietorship) that the sales guy can hit.

Finally, if you don't have a lot of experience with hydraulics, spend some time researching degloving to get proper motivation for your safety protocol. A small exo with no barrier between me and the hydraulic lines is not something I would get into.

  • $\begingroup$ The big problem with dumpster diving / eBay is finding a large number of similar matched components that can be designed around consistently. Regarding hydraulic and control safety issues, I am about 98% responsible for creating and citing the "Challenges and Limitations" section of the Wikipedia article for powered exoskeletons. Small, high torque, high voltage, low amperage direct-drive electric motor/stepper servos aren't really any better. A pinhole crack in a 600 volt wire is going to be as much fun to be around as a pinhole leak in a 600 psi hydraulic line. $\endgroup$ Jun 14, 2016 at 8:44

Like any company, a small engineering firm depends on its service vendors. Those vendors might include machine shops, welders, and paint shops. developing relationships with vendors is important not just to have someone to go to, but also for advice on the best way to go about doing those things. Many of those places will be small shops, and are happy to deal with other small shops.

Then there are parts vendors, like metal supply shops and industrial supply places. For industrial supply, try McMaster-Carr. They have everything from hydraulic motors, to nuts & bolts to haz-mat suits, and all of the prices are there. For metal, try Industrial Metal Supply. I get about 80% of my materials between those two sources.

Don't be afraid to call potential vendors for prices. You will find that many don't want to deal with low-volume customers, and talking to them on the phone is the easiest way to weed them out.

But still, it is not easy.


You are right that prices are not displayed for products aimed at industrial use on vendors websites. Catalogs are available and you have to ask for a quotation to get the price. I am not sure why this is, it might have to do with differential pricing based on the customer, clients often get discounts and for some major manufacturers they also get a webshop type access reserved only for top clients. Another reason could be that they want to make sure that if you start buying equipment from them the equipment "fits together", is compatible and is well suited for the goal of the project. They often ask you about the project fro which you want to buy equipments, which you of course are not obliged to disclose the project, but salesperson are well trained can help a lot in selecting the most well suited equipment, if you allow them to.

To answer your questions:

Or don't they worry about cost, and leave it to their employer to eat the cost as a part of doing their line of work?

No, they do not. Especially small and medium enterprises are very price sensitive and are constantly looking for less expensive solutions (please note the difference between solution and components).

Is it possible to "shop around" for low-cost engineering components?

To my knowledge it is not. The sites I have found (in Europe) that allow you to by industrial equipment are way more exponense then the the official suppliers with no webshop.

Industrial components are expensive and in my personal observation, vendors who sell similar quality have similar price ranges.

Building an exoskeleton will be particularly expensive, because of the safety requirements (you have to guarantee that it cannot hurt anyone with a probability of 10e-8). Safety certified industrial equipment is way more expensive then regular industrial equipment. There is no way around this.

If you want a more cost effective solution you can prove that you technology works in simulation ad/or on a smaller scale and try to get an investment based on results (either from Investors or from Kickstarter or similar).

  • $\begingroup$ For reducing design costs, I am focusing on simulation first using free tools like Blender, and DAZ 3D human models to work out form and fit. Once the design is developed, I am planning to use the free Fusion 3D to CNC components for an unpowered lightweight mockup, to demonstrate its real-life flexibility in public, in hopes of attracting interest in the design from someone big, like maybe DARPA. After that, the plan would be to use the funding to hire experts who know how to build a realtime self-collision detection and prevention system, among other safety systems.. $\endgroup$ Jun 14, 2016 at 9:17
  • $\begingroup$ To my knowledge the tools you mentioned are illustration tools and not design or simulation tools however, depending on your goals they might be ok. $\endgroup$
    – 50k4
    Jun 14, 2016 at 12:12
  • $\begingroup$ It was originally my intent to do this work using a constructive solid geometry modeler, however a problem with every CSG that I have looked at, is that they do not have flexible mesh and bone support. Importing a flexible human model from DAZ 3D into CSG turns it into an immobile statue, rendering it useless for motion studies. I did find a realistic muscoskeletal model for professional CSG called AnyBody, but they rent access to it for around $50,000 / year, making it inaccessible on my income. So unfortunately I have to use an imprecise 3D art modeler, to be able to use "cheap" DAZ models. $\endgroup$ Jun 14, 2016 at 17:18

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