Category Archive: Uncategorized

Bassmasters Comes to Minnesota

Minnesota is the land of 10,000 lakes, and home of some of the best fishing in the world.  And last week, one of Minnesota’s best lakes was put in the spotlight.  Located about 20 miles south of Stern Rubber’s Aitkin location is Mille Las Lake, which played host last weekend to the Bass Pro Shops, Bassmaster Angler of the Year Championship.  The Bassmaster series which started in 2006 is a circuit of professional fisherman that compete all season long, to get the opportunity to hopefully make the final event, and earn enough points to be able to return to the series the next year.  Only 50 of the 111 fishermen who compete even get the chance to battle it out for the $100,000 point’s leader payout.
The fishing at the event was some of the best in tournament history, which is no surprise to the locals of the Milles Lacs area.  After day one, the fishermen produced 23 limits of small mouth bass all weighing in at 20 pounds or more per limit, and the points leaders were in a tight locked battle, that took three more days of fishing to determine the champion.  In the end Gerald Swindle, the point’s leader coming into the Mille Lacs tournament, was crowned the champion and took home the $100,000 prize.
Although the tournament is exciting, the praise for the lake and the area from the competitors is even more impressive.  Mille Lacs, which has had its issues over the years, due to the reduced walleye population, is looking to rebound, by showing the rest of the country that there is more than just walleye fishing in the Mille Lacs area, and by bringing in the Bassmasters, they are doing just that.   Some of the best praise came from Michigan native and Bass Anglers Sportsman Society all-time money winner, Kevin VanDam.  “I have been to great smallmouth bass lakes in Michigan … to Lake Champlain … to Lake St. Clair.  No place has as many big ones as Mille Lacs.  The bass are crazy big in this lake,” said VanDam.  Having fishing greats like Kevin, brings Mille Lacs into the national spotlight, and is exactly what the area is looking for.
So the next time you’re in Stern Rubber’s back yard, whether you’re a professional angler or just recreational, try your luck on Mille Lacs and see if you can out fish the Bassmasters.

Stern Rubber Achieves ISO/TS 16949:2009 Registration

After months of work, Stern Rubber Company has received certification of registration to ISO/TS 16949:2009 for rubber compounding, as well as the molding and bonding of custom rubber products.  Stern Rubber has been registered to ISO 9001:2008 for 3 years.  During their recertification this year, the quality system was expanded to meet the additional requirements of the ISO/TS 16949:2009 standard.
Stern Rubber Company was purchased in October of 2015 by Zhongli Corporation, which is a supplier of automotive parts.  Prior to the purchase, Zhongli’s products were all manufactured in China, but they wanted to expand their manufacturing into North America, to support the North American automotive market.  This registration to ISO/TS 19646:2008 is one of the first steps for the Stern Rubber facility to expand into the automotive industry.
This registration is normally good for a 3 year period, with a surveillance required every year, and then a full recertification required in 3 years.  But, the ISO/TS standard was recently updated, and the update will be released in December of 2016.  All organizations that are certified to ISO/TS 16949:2009 have until September 14, 2018 to transition to the new standard.  Stern Rubber plans to go through a surveillance audit in 2017, and then the full recertification in 2018.

Tornado strikes Morrison County area

As the summer slowly comes to an end in central Minnesota, large storms continue to still affect the area.  With a year that already brought record rain in July (that we highlighted in an earlier segment), high winds, and a great deal of damage in August, it is only fitting that September would have a tornado.
On Wednesday, September 7th, an EF1 tornado producing wind speeds around 110mph touched down in the Fort Ripley area, about 40 miles from Stern Rubber’s Staples location.  At around 11 pm on Wednesday night, the Morrison county sheriff’s office was notified of a large storm capable of producing a tornado.
Within the next half hour, the storm ripped across Morrison County, overturning trees, flipping campers, damaging homes, and capsizing boats.  The storm continued about a mile and a half north to the Camp Ripley area where the storms destruction ended.  According to the sheriff’s office, the storm was undetected, developed quickly, and was very fast moving.
Camp Ripley took the brunt of the storm with a significant damage.  Several building used for housing and training and maintenance received major damage, including roofs torn off.  Also, a 10-megawatt solar farm that was set to be dedicated this week was dedicated by flying debris.
Another hard hit area was the Green Prairie Fish Lake area, and specifically Laurie’s Lakeside Resort.  At the resort, campers were moved, and tipped over, and several boats and docks were missing from the shore.
Within the last two years the area in which Stern Rubber is located has experienced, straight line hurricane force winds, record setting rain fall, several tornados and millions of dollars in damage.

Aitkin Facility Addition

Last week, we officially broke ground on a building addition to our facility in Aitkin.   We are doubling the size of the facility, taking it from 10,000 square feet to 20,000.  When this is completed, we plan to move some projects from our Staples plant, as we need the room in Staples for new projects.
The projects that we plan to move include a line of large gate valves that we currently manufacture in Staples.  We currently mold 4″ through 12″ gate valves in Aitkin, and 14″ through 24″ in Staples.  These larger sizes that are manufactured in Staples require the use of overhead cranes
for material handling, and the Aitkin facility has more ceiling height than what we have in Staples.  This will allow us to have a much better layout for material flow, than what the Staples facility allows.  The move to Aitkin also allows the opportunity to go to even larger sizes than the 24″.
The Aitkin project has taken longer to get launched that what was first expected, as we first had to buy out the lease on the building, and purchase the adjoining property,
so we could put on the size addition that made sense.  The current building was built and owned by Aitkin County Growth, which was a non-profit corporation based in Aitkin, MN, that operates as a business incubator.  They have a facility in town that they lease out, for very attractive rates, to entice people to open a business in Aitkin.  This was very key, for us to first move to Aitkin in 1997.  As we expanded and eventually outgrew the facility in town, Aitkin Growth built us a building in the Aitkin Industrial Park.  We moved into this building in 2004, and signed a 15 year lease.  Aitkin Growth was not interested in signing another long term lease, and build our next addition, so we purchased the facility from them,  We also purchased a small parcel to the east of the building, as the building addition put the wall right on the property line.
We have hired Hammers Construction from Perham, MN for a design/ build project.  A ceremonial ground breaking was held on July 19th, but the actual start of construction was Wednesday, August 24th, and the concrete was completed on Wednesday, August 31st.  We expect the building to be completed in approximately 14 weeks.  Keep checking back, as we post pictures of the progress!

2016 International Rolle Bolle Tournament

The 2016 Annual International Rolle Bolle (row-lee bow-lee) Tournament was held August 11-14 at two different venues, one in Marshall, Minnesota and the other in Ghent, Minnesota, which is known as the Rolle Bolle Capital of the World.  The event was hosted by Chauncey Welvaert and his team of volunteers. The International brings in Canadians from Winnipeg and beyond, plus Americans from Illinois, Iowa, Wisconsin, and Minnesota. Good sportsmanship and fun were seen everywhere.  Off the court, all the waiting players and their friends and families, were picnicking, playing cards, texting or catching up with friends from elsewhere.

What the heck is Rolle Bolle you ask?  Well, it’s Belgian Bowling with a twist.  Instead of a ball they use a 6-8 inch diameter by 2 ½ inch thick, solid, hard-rubber wheel that looks like a giant hockey puck.  Rolle Bolle is sort of a cross between Curling and Horseshoes played on a 42 ft. long alley with 2 stakes placed 30 ft. apart.  The object is to roll your bolle to the other end of the alley, as close to the stake as possible.  Then your opponent has the choice of trying to get closer than you, or trying to hit your bolle away from the stake.  There are three people on a team and the first team to eight points wins.  Oh yes, did I tell you the circumference of the bolle is machined at an angle so it doesn’t roll straight?  That’s the twist!  That angle determines how big a curve the bolle takes as it’s rolling to the stake.
The origins of rolle bolle are unclear.  Some theorize that the game originated in Belgian iron foundries more than a hundred years ago.  The axles of ore-filled slag cars bent due to excessive weight, wearing down the inside of the cars` wheels.  As the wheels were discarded, workers started rolling them for fun, and the game soon developed.
Now that you know a little about Rolle Bolle, let me share what I learned about the game this past weekend.  First of all, it’s not a bunch of Belgian Farmers getting together for an excuse to drink.  This was a family outing, a four day event that brought families and generations together.  In the Class B Men’s Championship, both teams had 3 generations on their team (son, father, and grandfather).  In the Novice Championship, the winners had two sisters and the runners up, was a mom and her two daughters.  The runners up of the Men’s Class A Championship had two brothers and a cousin.  Between matches, young children were on the alleys, playing with child sized bolles.
I asked a lot of young people, who taught them how to play?  The answers were my brother, my mother, my grandfather, my grandmother, my brother, my sister, always family.  Maybe that’s what America needs, a lot more Rolle Bolle and a lot less phone apps.
My wife and I met a lot of new friends during the weekend and I can say it made me very proud of my Belgian heritage, and proud that the company I work for, Stern Rubber Company, molds, bonds, and extrudes rubber parts including the bolles used in Rolle Bolle!

Injection Molding

In the last two weeks, we wrote about the 3 main types of molding that we do at Stern Rubber Company: compression, transfer and injection.  This week, we will discuss injection molding in detail.
Injection molding is different from transfer or compression molding, in that it takes a specific injection molding press.  This type of molding is somewhat similar to compression and transfer, as they all run at high hydraulic pressure, and have electrically heated platens that are run in the 300 to 400 degrees Fahrenheit range.
An injection press has an injection unit that is usually mounted on the top of the press.  There is a screw extruder that takes in the rubber material and pushes it into the injection ram.  The material is warmed in the extruder and the injector.  The ram then shoots the rubber into the mold through a runner system that is cut into the mold.  A computerized control system controls the entire molding process, from the volume of material, to the injection and clamp pressures, and the cure time.  The controls on the newer machines monitor and track any number of parameters and can do SPC calculations on those parameters.
Injection molding is good for medium to high volume parts.  It is not usually good for low volume parts, as there is a longer set up time to get the mold mounted in the press, and there is material that is wasted that has to be ran into the injection unit to push out the previous material.
Injection molding is good for rubber to metal bonding, just like compression and transfer molding.
Here at Stern Rubber, we currently have Desma and Rutil injection presses.  A few other brands include Maplan and Rep.
Like compression and transfer, injection molds are made from steel or aluminum.  The shape of the part is cut into the mold.  The main difference between injection tooling and the other types is that the tools have a runner system where the rubber is fed from the injector into the cavities.
The tool is held closed for the given cure time, and when the tool opens, the runner system is removed, and the parts are removed.
The advantages to injection molding are reduced cure times, less flash to remove after molding, and the ability to hold tighter tolerances.  The shorter cure times are possible due to the pre-heating of the material in the screw and injector.  Because the tool is clamped shut before the material in injected in, it is possible to mold parts with much less extra flash that has to be removed, and allows for less variation in size, so tighter tolerances.
The main disadvantages include longer set up times, and more material used at start up and in the runner system.
If you have want to learn more about this process, or think you have a project that will be a good fit for injection molding, please contact us at

Transfer Molding

Last week, we wrote about the 3 main types of molding that we do at Stern Rubber Company: compression, transfer and injection.  Last week we discussed compression, and this week, we will cover transfer molding.
Transfer molding is similar to compression molding, as they are run the same presses.  These presses are run at high hydraulic pressure, and have electrically heated platens that are run in the 300 to 400 degrees Fahrenheit range.  The difference is all in the tooling, and not in the press.  Similar to compression, it is good for low to medium volume parts, and can be used for high volume parts, if the part is small.  Transfer and compression molding are both good for rubber to metal bonding.
Here are a few links to learn more about the presses that we use for compression and transfer molding, from some of the suppliers where we purchase presses.

Presses & Parts

Like compression, these types of molds are made from steel or aluminum.  The shape of the part is cut into the mold.  The main difference between compression tooling and transfer tooling, is that in transfer, the rubber is fed, or “transferred” through small feed holes from a “pot” into each cavity.
In transfer molding, you can place one large piece of rubber material into the pot, instead of having to load rubber in each of many cavities.  A simple part that is molded compression can be made on a 2 plate mold.  Half of the part cavity is cut into each half of the mold.  With transfer, you still have the 2 cavity plates, but in the top plate, you have to add the feel holes, and on top of the top plate, we add the pot, and aluminum plunger, or lid that forces the rubber through the feed holes and into the cavities.
The tool is held closed for 5 to 15 minutes depending on the thickness of the part.  When the cure time is complete, the tool is opened, the flash pad is removed, and the part is removed.
The advantages are very similar to compression molding as they both include lower cost tooling, and are both good for small production runs, as the set up time is normally very low, as the tool normally just has to be slid into the press and heated, and it is ready to run.  There is also no wasted material for set up, as you load the rubber into the tool, and do not have to use rubber to clean out the injection unit, like we do with an injection tool.  As in compression molding, transfer molding is also a good way to produce large parts that take a significant amount of material, or a long cure time to manufacture.  The one advantage that transfer does have over compression, is that it is much faster to load the material, as discussed above.  This also reduces the material prep time.  Transfer also usually allows for less flash than compression, and therefore we can usually allow tighter tolerances than compression.
Some of the disadvantages include slower process times compared to injection, and greater waste of material, even when compared to compression.  With transfer, we have the waste of the material that stays in the pot and feeds.  The tolerances that can be held are still not as tight as injection molded parts.
If you have want to learn more about this process, or think you have a project that will be a good fit for compression molding, please contact us at

Compression Molding

Here at Stern Rubber, we do 3 main types of molding: compression, transfer and injection.  Over the next 3 blogs, I will describe each of them in detail, and will start with compression molding.
Compression molding is the most simple of the three, as you load rubber into the cavity, close the tool, squeeze out the extra, and let it cure.  It is good for low to medium volume parts.
These types of molds are made from steel or aluminum.  The shape of the part is cut into the mold.  The tool is run into a hydraulic press that has heated platens.  The rubber has to be held at high pressure and high temperature.  The platens can be heated by electric heating elements or hot oil or steam.  Stern Rubber uses all electrically heated platens.  Parts are normally cured at a 300 to 350 degrees Fahrenheit.
The tool is heated through simple contact with the platens of the press.  The rubber is loaded in the cavity of the mold, and the tool is closed.  Any extra rubber is squeezed out of the cavity.  The presses run at high pressure, with clamp pressures from 10 to 1000 tons.
The tool is held closed for 5 to 15 minutes depending on the thickness of the part.  When the cure time is complete, the tool is opened and the part is removed.
The advantages include lower cost tooling, and it is good for small production runs.  It also does not use gates, sprues, or runners, which consume extra material, and can detract from the cosmetic requirements.  It is also a good way to produce large parts that take a significant amount of material to manufacture.
Some of the disadvantages include slower process times, and greater waste of material, as this type of molding requires the cavity to be over-filled to ensure there is enough material to wash out any possible trapped air.  It also difficult to control the amount and thickness of flash, or the extra rubber that overflows out of the cavity.  This also means that the parts have more variation in thickness, so the parts normally need to allow for more dimensional tolerance.
If you have want to learn more about this process, or think you have a project that will be a good fit for compression molding, please contact us at

Paul Bunyan Extreme 5K – Mud, Sweat & Fears

On the second Saturday of July each year, Mount Ski Gull, northwest of Brainerd, hosts the Paul Bunyan Extreme 5K.  The race is made up of over 20 insane obstacles spread out over a 3.2 mile course covered in hills, mud and challenges!  Some of these challenges include water slides, rope swings, mud pits, and more, some being man made, and some by Mother Nature.  The course is set up to be a friends and family event, and it is set up to challenge people of all ages.  The year’s event was held on July 9th.
Ryan Trout, a 2016 graduate of Staples-Motley High School was this year’s winner.  Ryan was a cross country and long distance rubber and pole vaulter for the Cardinal’s athletic team.  We won with a time of 26:38, beating his 2015 time of 30:18.  Trout said the most challenging portion was the downhill slalom obstacle called the “Alpine Challenge”.  He ran early in the morning, and there was dew on the grass, which made it very slippery.
Coming in second place was Stern Rubber’s own Cyris Eagle Tail, with a time of 28:24.  Cyris is our molding lead on third shift.  He keeps in shape with a lot of running, and he often runs to and from work.
At the end of the event, Pillager Area Fire & Rescue is standing by to rinse away some of the mud.
If you are up to the challenge, come on out next year!
Here is a link to the 2016 results:
Here is a video of the 2015 event:

Mother Nature Is At It Again in Central Minnesota!

On July 12th, 2015 Central Minnesota was hit with a massive thunderstorm with hurricane force winds.  The storm caused millions of dollars of damage to buildings and trees, including 3 of the largest resorts in the area, Madden’s Resort, Cragun’s Resort and Grand View Lodge.  Some of the golf courses owned by these resorts were closed for weeks for tree cleanup.  Madden’s Resort was hit the worst with several large building destroyed.  They rebuilt these buildings and had them open for Memorial Day weekend in 2016.
On the anniversary of that storm, the same area was hit with a huge rain event.  Brainerd, MN, which is just 30 miles east of Staples, was hit with 8.78 inches of rain between the night of July 10th, and the early morning of July 12th.  Brainerd only averages 7.66 inches of rain during the months of May and June combined!  That is the most rain in that short of a period of time since records started being kept in 1908.  There were locations nearby that had over 10”.  The Staples area had 6 to 8 inches, depending on where you were located.
The only way that the company was affected was that the employee parking lot and loading docks were flooded.
Here are some highlights from the storm.
The storm dumped six inches of rain or more over a 2,000 square mile area!
The Bad River near Ondanah, Wisconsin broke its record high flood mark when it hit 27.28 feet.  The previous record was 22.2 feet.
One of the hardest hit areas was Fish Lake, where the water was rising three inches per hour.
In Moose Lake, a half million gallons of untreated sewage poured into Moosehead Lake when their sewer system became inundated with flood waters.
On Wednesday, July 11th, Willow River issued a voluntary evacuation order, when high water flowed over the top of the town’s dam.
The Snake River, near the City of Mora, raised from 3 feet to 16 feet in one day.
It was reported in Aitkin County, where one of our facilities is located, that based on the amount of rain in a short time, that it is a 500 year storm.  In fact, the National Park Service called it a thousand year flood!  The Brainerd Daily Dispatch called it an 800 year storm, so you can see that everyone thought it was impressive!
The worst part of this disaster is that at least three people were killed in northwest Wisconsin.
Here is some video of the flooding in the Fish Lake area: