Posts Tagged ‘Wheels’

History of the Small Bottle (SB) Rotary Blow Molder

Wednesday, September 28th, 2016



The Story of Wilmington’s Small Bottle (SB) Blow Molding Wheel

We had a customer visit a couple of weeks ago and asked the question about how and why was the SB technology developed. Wilmington Machinery was the first company to specifically design a high speed rotary extrusion blow molding system for small bottles and there was a very specific reason for that.

First let me start by explaining the SB technology refers to Wilmington’s exclusive technique of blowing a bottle with a capture neck parison (no flash around the neck) and a mold design with no bottle knockout devices, no cut off knives between the molds and no bottle takeout mechanism. The bottles are spin trimmed and do not require deflashing. Reaming of the neck internal diameter is optional as a secondary operation.

Several years earlier while doing development work in our lab, a customer wanted to conduct multilayer trials on a small container in a typical neck-to-neck configuration.  These containers were being retorted and sidewall paneling was a particular problem so material distribution was critical as was the statistical significance of certain wall thickness measurements. As hard as we tried, we could never get the top and bottom container perfectly identical and we always had a bi-modal statistically distribution of wall thickness at the base of the bottles.

So the idea was born to build a wheel with small clamps that could handle much smaller molds than had ever been done before on wheel machines. Individual bottles could be placed in each mold and all bottles oriented in the same direction. This would guarantee that every bottle would be identical because they were blown from a single parison using the same tooling and same parison profile. The first wheel manufactured was for drinkable yogurts which had 24 stations and could make 240 BPM. It stood only 6 feet tall and everyone was amazed at how many bottles it could produce for such a small machine.

The next challenge was that the majority of the small single serve bottles were concentrated in the dairy, juice, drinkable yogurt and the growing nutritional / supplement market. These bottles were light weight and some could run at very fast cycle times with some in the 5-6 second range. This meant bottles would be discharged from the wheel at possible speed up to 1000 parts per minute and a traditional bottle takeout system had never been built to handle these speeds. Based up on some previous experience of trimming bottles in the mold, a very unique mold design was developed that would both trim and discharge the bottle to a bulk conveyor without the need of pneumatic knockout system, no cut-off knives between the mold and no complicated bottle takeout device. This was made possible because the mold and process design also blew and cooled 100% of the flash eliminating the risk of the bottles sticking together prior to trimming.

Today the technology has been expanded in to multi-layer and dual parison applications with plans on the board to extend to 3 parison configuration. To learn more and understand if this technology could be applied to your application, contact Jeff at Wilmington Machinery.

SB Rotary Blow Molding Machines

Monday, March 7th, 2011

I have talked with many customers over the last several months about our high speed “SB” Rotary Blow Molding (RBM) systems for small bottles. The applications have been expanding as the process works for any where the parison is contained in the neck. The advantages that they all say we have as compared to other shuttles, recipes and wheels are:

• No complicated takeout systems or bottle knock out devices

• No complicated tooling (shear steels, blow pins, deflashing, etc) to maintain

• High operating efficiencies of the production line

• No complicated hydraulics and greater energy savings

• Much small machine requiring less floor space

• Because of the simplistic design it requires less people

• Much high quality bottles than can be made on other type of machines

Recently I talked with a customer that said our competitor told them the SB process “does not work”, I said “does not work, what do you mean?” the competitor says that your machine produces unblown bottles, the process does not work with no tails and it takes 3 people to run the line”. So I then put him in touch with a customer that has been running our SB system, very successfully, for 4 years. After the conversation he told me “you are right, he loves his machine and says he has less than one operator”. The moral of the story is, don’t believe what you hear from competitors. With the Wilmington’s SB system, things CAN BE too good to be true. It’s simple and better than any other process on the market today, I hope you will call me to find out the truth about the SB RBM systems.

910-431-1003 or email me at:


Blow Molding Process Comparison

Wednesday, April 7th, 2010

If you are new to blow molding or if you have been in the industry for 30 years, it can still be confusing as to what type of blow molding machinery or process is best for your next application. I have been fortunate in my career to design and build machinery for every type of blow molding process. For your information I consider there to be 7 primary machinery processes for packaging applications.

Shuttles (Continuous extrusion)
Wheels (Continuous extrusion)
Injection Blow
Injection Stretch Blow (1 Step)
Reheat Stretch Blow (2 Step)
Reciprocating screw (Intermittent extrusion)
Accumulator Head (Intermittent extrusion)

Some people may refer to them differently and some may argue several of these should be grouped together, but for sake of discussion, we will use this grouping. Further definition of the technologies, along with pros and cons for each process, can be found in the links above.

  Shuttle Wheel Injection Blow Injection Stretch (1-Step) Reheat Stretch (2-Step) Recip Screw Accumulater HD
HDPE Yes Yes Yes No No Yes Yes
PP Yes Yes Yes Sometimes No Yes Yes
PET No No Yes Yes Yes No No
PVC Yes Yes Yes No No No No
Styrene No No Yes No No No No
Multilayer / coinjection Yes Yes Difficult Difficult Difficult No Difficult
IML Yes Yes No No No Difficult Difficult
Handleware Yes Yes No No No Yes Yes
Injection Finish Good Fair Excellent Excellent Excellent Fair Good
In-machine Deflashing Yes No N/A N/A N/A No No
Flashless Process No No Yes Yes Yes No No
Small Bottle<100 ml

low/med vol.

Yes No Yes No No No No
Small Bottle<100 ml

high vol.

Yes Maybe Yes No No No No
Med. Bottle(1 litre)

low vol.

Yes No Yes Yes No Yes No
Med. Bottle(1 litre)

high vol.

Yes Yes No No Yes Yes No
Large Bottle(4 litre)

low vol.

Yes Yes No No No Yes No
Large Bottle(4 litre)

low vol.

No Yes No No No Yes No