Consider When Designing Products - abs plastic molding

Thermosets or vulcanates like natural rubber can be compression molded, injection molded, or compression/injection molded. Same process as above but natural rubber has a higher stress/strain than most TPE so you can pull enormous mandrels out of tiny holes. And when it comes to elastomeric materials natural rubber is incredibly durable

For anything I’ve seen rotomolded I always felt like it was larger parts, poor exterior surface quality, and usually the higher cycle time makes it not great for super cheap stuff.

If you are thinking of importing PVC products, be aware that they can contain material that is prohibited for sale in California or prohibited for sale without labeling. The law is called Prop 65. The list of materials is available here: https://oehha.ca.gov/proposition-65/proposition-65-list As a designer, you can’t really validate this in your garage, but inspection services can. Some services are Bureau Veritas, SGS, MTS or contact a testing laboratory. Even in Canada, most labs have a prop 65 testing protocol.

Steck: They stock up shelves with an assortment of hardware like screws, nuts, and washers, and the supplier comes in once a week to do inventory and replace what's needed.

Steck: I would suggest that they provide more support for small businesses looking to build a print farm, such as discounting continued purchases and helping them find the right materials. Additionally, there is a need for support with finishing and painting for smaller businesses. Leveraging a larger company's research and development capabilities and exposure to different markets would be beneficial.

Is it blow molding or roto molding?I always assumed roto and then they IP the squeaker and either insert mold it or assemble it post.

Looking at this for a client and I’ve searched the internet. Any kid or pet toy that has a hollow center made out of soft durometer material. I figure it’s some sort of a blow molding process. Some toys have open ends on them but I wouldnt think you could pull a core out of it without ripping the material. Help anyone?

Steck: Yes, we've had to train our staff and even hire new engineers with more CAD experience. But it's been a worthwhile investment, as we can take advantage of the investment tax credit for purchasing new equipment and increasing our competency in new technologies. We're also making room for more 3D-printing machines by getting rid of old technologies that require more floor space and replacing them with newer, more efficient machines.

But, there are so many other options now. They're actually making injection molds out of 3D-printed materials; they're doing carbon-fiber composites that are post cured and are very strong structurally and resilient; and, of course, they're printing metals. Jet engine parts are now being printed that couldn't be made that way in the past. The whole manufacturing industry is being modernized by 3D printing. The US Navy and military are deploying 3D printers now to reduce their inventory of consumables.

Blow molding is a good technique for molding these toys but mostly if the product has to have a relatively strong and lightweight outer shell. It also has a cycle time at least 10x faster than rotational molding. But the advantages of rotomolding are that it works for more types of polymers including soft PUs, tooling costs are much lower, and it is easy to experiment with production parameters. That is the reason why these toys are often rotationally molded.

Latex is slush cast or slipcast just like ceramic in plaster molds. slightly more durable than vinyl depending on how you measure but with a much shorter lifespan.

TPE’s, a very wide class of Thermo PLastic Elastomers can be blow molded or injection molded. (in my experience vinyl and pvc used for blow molding is rigid and not the same low durometer “squeakable” stuff used in rotocasting). In blowmolding there is obviously no core but you have wall thickness limitations. When injection molding there is a core or mandrel suspended in the mold cavity. For minor undercuts you can use the ejection stroke to remove the mandrel if you design the tool right but in most cases of hollow parts its a manual process where the part and mandrel are removed after each shot, mounted on a fixture and either leveraged off with brute force or if there are no other openings in the part you can run an airline through the mandrel and blow compressed air through to launch the parts off like a rocket.

Paul Steck: With our focus on 3D printing, we have been able to attract incremental business from our existing customers. It also builds on our core competency of finishing and machining. In our market, which is low-volume manufacturing of large-format parts, it is likely that as we progress, we will become more sought-after not just for prototyping, but also low-volume production. I should add that the pace of technological change in 3D printing is head-spinning, making it hard to keep up. What was groundbreaking just a year ago is now available at half the price with even better performance. For example, our new large-format 3D printer now has upgraded software available for a nominal charge, tripling the speed and improving resolution. It's like having a whole new printer for a fraction of the cost!

You answered your own question, it’s blow molding. Soft elastomer materials are pretty easy to yank tools out of, especially if the material is still warm. Theres also collapsing cores and other options.

Steck: Our company has invested in higher density racks and storage and eliminated mezzanines, which were not as efficient. We have also added more people to the building and continuously tweaked the operation to increase efficiency. This has resulted in a busier shop with more sales, but it appears more organized and open due to our efficiency improvements. Additionally, we are exploring the possibility of a deployable operation that would be convenient for the customer and eliminate the need for big heavy mold presses and expensive molds. By renting a space nearby or even setting up within our customers’ factories, we would be a more valuable supplier.

Steck: One thing we are seeing is increased demand for 3D printing of parts that cannot be conventionally tooled, even in quantities. We are incorporating more and more printed parts into our assemblies to meet customer requests. We have also discovered new materials that are UL 94 certified, meaning they are fire retardant or can stop flame spread. Our customers appreciate this innovation, and we are constantly on the lookout for new developments to expand our offerings. We have already introduced our customers to UL-certified materials that they were previously unaware of. We are on our third generation of 3D printers, moving toward our fourth, and expanding our capabilities with each new upgrade.

PlasticsToday: Although progress has been exponential, as you say, you would agree that 3D printing still has some limitations?

Exothermic Molding Inc. is a reaction injection molding company founded in 1972 that initially served the medical, electronics, and lab instruments market. Since then, it has expanded into many other applications and sectors. President Paul Steck attributes a large part of the company’s success to a culture that prioritizes research and development and investment in skilled personnel and training. In recent years, 3D printing has played an increasingly important role in Exothermic Molding’s R&D program. In this Q&A, Steck explains how 3D printing has helped his company stay ahead of the competition and take advantage of new opportunities.

PlasticsToday: The concept of setting up a shop within a store, like cosmetics counters, has been done in retail. Could it work in manufacturing?

Vinyl/PVC toys like bath toys and the cheapest dog toys are usually rotocast in a bank of molds that get filled with liquid, pelletized or powdered raw materials. This goes in to a furnace, spins real fast and then comes out to cool off, the toys are ripped out of small opening in the mold which creates a sloppy area on the part and its usually trimmed and filled in with a molded plug that would house the squeaker. This can also be done in a slush casting process using a vinyl plastisol. In some cases you might rotocast liquid RTV materials. Most of these materials are not highly durable.

Steck: Yes, it's a model used by hardware suppliers who have a store within the manufacturing facility to manage inventory. We could use this model for components instead.

Haven’t done any squeeky toys myself, but for the dog toys I’m thinking of, I would have assumed blow molding since usually there is a good smooth finish and an obvious clamp mark for a gas injection point, plus the smaller size and surface finish.

PlasticsToday: There's a small company called Tyber Medical that's growing by supplying missing orthopedic parts in a supplier’s product line. Could this be a market for 3D printing?

I’ve always used roto casting too, with spray ops for any deco. Like Ray mentions, you really need to watch out for some of those materials, especially including Phthalates, which are commonly used to soften material used in roto casting.

As an aside to the manufacturing of the outer, if you’re looking for it to make any noise you can have some fun playing with different bellow sizes and different reeds for a great range of sounds! And they don’t all need to be reeds, they can be compression and even things that you bend that make unusual sounds! Great fun to play around with, really makes you feel like a kid!

@ralphzoontjens could you please re-post the link to the video of how squeakers are made? The link you posted previously no longer works. If anyone reading this can help with the link or has a similar video they can share it would be greatly appreciated!

Editor in chief of PlasticsToday since 2015, Norbert Sparrow has more than 30 years of editorial experience in business-to-business media. He studied journalism at the Centre Universitaire d'Etudes du Journalisme in Strasbourg, France, where he earned a master's degree.

Exothermic Molding President Paul Steck explains how the addition of 3D-printing capabilities helped him to grow his business and enter new markets.

Steck: By increasing our build space from 20 inches to over 40 inches, we can now create larger parts and take advantage of new opportunities in markets where larger parts are in demand. In the past, we focused mainly on medical instrument housings and test equipment, but now we can expand into other verticals and offer sub-assemblies for our current customers.

on my first trip to China i saw a part from my company that was 8" in diameter with a .4" wall thickness that was molded over a steel core that was pulled out of a 1.5" opening in the part. The part had nearly a 10 minute cycle time, two cavity mold, when the parts came out 1 worker would pick up the core and part, and hang it from a fixture while two dudes with bulging biceps used tire spoons to wrestle that part off the mandrel. At this point there have been millions sold.

Steck: Absolutely, it's a market that anyone with a printer could get into, not just insiders. It's a matter of having the vision to try something new.

Thanks guys. I wish there was a video of this process. Normally I can just youtube any manufacturing question and see it on youtube or on old clips of “how things are made”. I’m curious if they use a rotomolded process, they must do multiples of them and I envision they put these molds or mold (with multiple cavities) on a rotating 2-3 axis mechanism.

Steck: Yes. Lower barriers to entry have allowed small businesses to compete with larger ones in the manufacturing industry. 3D printing, aka additive manufacturing, has made it easier and more cost-efficient to create and develop products. This technology allows for shorter research and development cycles, eliminating the need for expensive molds and lengthy development time. Additionally, this technology has the potential to disrupt the entire distribution network, as it allows for print-on-demand services, eliminating the need for physical inventory and warehousing.

I recommend vinyl because it looks great and can be downcycled into flooring. You can look into extrusion blow molding TPE or EVA but it will likely require some R&D before the factory gets it right.

On my last trip to China i saw a pneumatic machine that i designed to help bring some automation and robot assistance to this process on the production line of every rubber supplier i visited, i only ever sent the plans to one supplier.

PlasticsToday: Overall, would you say that 3D printing has made it easier for small businesses to compete with larger ones?

Steck: Yes, parts still come out somewhat rough and require finishing. However, this opens up opportunities for us to offer finishing services for others. We're also exploring the possibility of hybridizing our 3D printing by printing faster at a lower resolution and then machining the parts for higher tolerances than what can be achieved through printing alone. With our expertise in machining and mold making, we can offer inventive solutions for large-format 3D printing.

But I admit I could be wrong and just basing those assumption on samples I saw long ago. Never touched either process in my line of work.