How to Set Up a Heat Shrink Wrapper
Have you recently bought a heat shrink wrapper, or are you considering buying one? The question of how to set up the machine is fundamental. If you are unsure which device to use, check out our guide about what shrink wrap machine is right for your business. People often ask if many tools or knowledge are required for setup. Before broadly answering this question for a blog post, we must first point out a few common styles of heat shrink machines. From there, we can offer an idea of the general setup and what may be required. It is important to remember all machine brands are different and can instruct different settings for proper setup. We highly encourage reviewing the instruction manual for the machine before operation.
What style of shrink wrapping machine are you setting up?
Impulse sealer and heat gun Setup
Impulse sealers are an excellent solution for lower production packaging while offering a professional look. When you receive the sealer, it is essential not to throw away the extra sealing wire that comes with the machine. With enough heat and seals, the sealing wire will eventually burn out, and the replacement will be necessary to continue production. Be sure there is a source for more before buying the sealer. Not all wires fit every sealer.
Impulse Sealer Setup
The impulse sealer itself should be very simple to operate and set up. The numbered sealing timer dial will be located on the front of the sealer. The timer turns off the heat at the set time. The sealing light will turn on when sealing begins and off upon completion.
A PVC shrink wrap or standard polyolefin film should be used with an impulse sealer. Shrink bags are often preferred because only one open side needs to be sealed. The material's thickness will impact settings; we recommend a setting of 3 to begin with most polyolefin thicknesses and a 2 with PVC materials.
After the seal timer is set, place the desired side to be sealed into the sealer and close the arm. As the sealer engages the microswitch, a clicking noise should sound. This should signal the sealing timer to come on. Once the light shuts off, keeping the sealing arm pressed down is very important.
Pull the excess film from the sealer as the arm is pressed down. If the material does not easily tear away after the sealing light is off, with the bar down, the sealing time will need to be increased. It is important to slowly increase the seal time until the excess material quickly pulls away from the sealer after completion.
The lower the sealer can be run, the longer the sealing wire will last. That is why making minor adjustments is crucial until the correct temperature is found. Over time and with enough seals, a residue will build up on the tape over the sealing wire and require it to be changed or increase the sealing time.
The best way to make sealing wires last longer is prevention. Operating the sealer with the lowest timer setting while still accomplishing a quality seal will help tremendously. The first line of defense in protecting the sealing wire is the Teflon tape. Buying a roll of Teflon tape to replace the existing strip when burn holes and residue appear will help increase the life of the sealing wire.
After the first seal is successfully made, a pocket forms for products to be inserted into the shrink film, two more seals will need to be made to enclose the product entirely. Seals should be made a quarter to half an inch away from the product edges.
Heat Gun Setup
When using the heat gun, it is recommended to begin at a low setting. The end of the heat gun can become hot quickly, and if held too close, burn holes will happen swiftly. Hold approximately 12-16 inches from the material with the heat gun on low. Always keep the gun moving without letting it stay in one place. Go around the sides of the products first, and they should tighten and pull the shrink film around the product. Finish up by quickly heating the front and the back of the product.
If burn holes are found, the heat gun was too close or left in one spot for too long. If the material is not shrinking and high heat is used, be careful with the end of the heat gun. It will become hot and cause burns if not adequately monitored.
I Bar Sealer and Heat Gun Setup
The primary difference between the I bar sealer and impulse sealer is the film rack with the I bar sealers. The setup for both machines is often the same and can be completed within minutes.
Most of the setup for an I-Bar sealer mirrors the impulse sealer setup. We want to quickly explain the film dispenser because it is a critical step often missed. In front of the film roll holder is a film separator.
A centerfold roll should be placed on the dispenser with the open end facing the operator. Pull some material out and separate it apart. The bottom side of the material should go under the separator bar, and the top should go over the bar.
The rest of the setup is like the impulse sealer explanation above. Be sure not to throw out extra wires that come with new machines, and follow the longevity tips explained above to increase the life of your sealing wire.
One-Step Shrink Chamber Set up
The shrink chambers or one-step machines are favorites for offices and work areas with limited space. They seal and shrink in one cycle. Due to the lid opening and closing, heat can escape, and the machine will need to reheat before wrapping another product. If operators do not wait for the indicator showing the machine is ready, products will never look satisfactory.
Unloading & Electrical Checks
First, remove the machine from the pallet and check the power cord. If 220v, there is a good chance you will need to put a plug on the device before use. Once the plug is installed correctly, ensure the machine gets the proper voltage and amperage. It will never perform appropriately without the correct power supply.
After the electrical is confirmed, the film rack may need to be installed before shrink wrapping. Each machine is different, and the setup can vary. Most film dispenser installations can be done within minutes and do not require many tools.
Film Threading and Chamber Adjustments Before Sealing
Threading the film onto the film rack is one of the most crucial parts of a shrink chamber setup. Read the instruction manual for your machine or a threading diagram sticker to properly thread the material on the device. Be sure to use the film perforators if available. They make small holes in the shrink film to allow air to escape the package. This allows the shrink wrap to conform to the product being wrapped without trapped air.
Before the first seal, ensure the chamber's product basket is appropriately adjusted. The sealing wire should be in the middle of the product from top to bottom. This adjustment is vital for ensuring the seal seam will not become distorted and uneven during the shrinking process.
Seal Time Adjustments
Most shrink chambers will have sealing time, shrink time, and temperature settings. Begin with the seal time close to a one or the lowest setting available. The seal time should be the most effortless adjustment to make. Once set, without adjusting the heat and shrink time settings, lower the lid and attempt to make a seal. Some one-step machines have a seal-only option that works great for determining the correct seal times.
Once the lid opens, see if a clean seal and cut have been made. The seal should be strong and not quickly torn apart. If a durable seal has been made, while cutting the excess film, leave the seal time alone and move on to the next step. If a seal was not formed or extra material is not cut, slowly increase the seal time until the correct setting is achieved. Be sure no small film strings are coming off the sealed material. These are known as angel hairs and cause too much heat exposure. To eliminate this problem, you will need to lower the seal time settings until a seal and cut are possible without noticeable angel hairs.
Temperature & Shrink Time Adjustments
Once the seal time adjustments are made for adequate closure, the temperature and shrink time will need to be adjusted. For these machines, we recommend a starting point of 350 degrees Fahrenheit. Allow the machine time to warm; an indicator should change to show when the device is ready for use. The last adjustment will need to be the shrinking time. Begin with it set in the middle of the available range. With the machine ready for operation, try a cycle. The sealer should seal and cut when finished, and the blower fan will power on to circulate hot air through the machine. Once finished, the fan will shut off, and the lid will open. Inspect the product for holes and tight fits in the corners. If there are burn holes in the material and total shrink, reduce the shrinking time until there are no more burn holes.
If the material is not shrunk all of the ways, slowly increase the seal time until you reach the desired shrink rate. If you max out the shrinking time and the material does not conform around the product, increase the temperature setting. The goal of setup is the correct-looking package but at the lowest temperature possible. It is better to max out the shrink time than the temperature if possible. The lower temperatures will keep from excessive wear on parts. If you are using a material thicker than 1.5 mils it may be difficult to obtain a full shrink rate and a shrink tunnel would be a more suitable option.
L Bar Sealer + Shrink Tunnel Set Up
Shrink combo systems combine an L bar sealer and shrink tunnel as one unit. Several manufacturers, foreign and domestic, make shrink combo systems. Not all models, but most have a transfer conveyor that moves products from the sealer to the shrink tunnel.
Unloading & Electrical Checks
Due to the size of a combo machine, it will need to be uncrated and removed from the pallet. If the device is a 220v model, a plugin may be required. Be sure the proper amount of voltage and amperage is coming into the machine. This can be found in the machine's user manual and back tag. Without the correct electrical supply, the tunnel will have difficulty warming up and maintaining set temperatures.
After the electrical supply is confirmed, the film carriage will often need to be installed. Few tools should be needed for installation. Once the film rack is installed, film threading must be done correctly. The instruction manual or a sticker on the machine should show the correct way to thread the shrink material. This step is vital because if not done correctly, the shrink film can tear before making it to the operator forcing package redos and slowing production.
L Bar Sealer Setup
After the proper film threading, turn the machine on and set the seal time to a one for your first seal. If adjusting a sealer with a hot knife, begin with the temperature to 300 degrees Fahrenheit. Pull the material into the sealing area and close the sealing bar. Once the sealing bar opens, check the film to see if a seal and cut have been made. If a smooth seal has been made, proceed to the transfer conveyor adjustment. If a seal and cut have not been made, slowly increase the seal time until a consistent seal is attained. For a hot knife sealer, increase the sealing temp no more than 20 degrees Fahrenheit until a seal and cut are made. If you can not correctly adjust the sealer, check out our shrink wrap troubleshooting guide for more information.
The transfer conveyor moves products from the sealing area to the shrink tunnel. Base model combo systems may not have a transfer conveyor. Proceed to shrink tunnel adjustments if you do not have a transfer conveyor. In addition to a product transfer conveyor, some machines have front-to-back tunnel adjustments. These adjustments line the product up to transfer through the center of the shrink tunnel.
The length of the product will determine the adjustment for the transfer conveyor. For smaller products, adjust the conveyor to run longer. The conveyor will not need to run as long for more oversized products. The conveyor should shut off once the front of the product reaches the shrink tunnel belt. Many brands of sealers will not allow the heating element to work until the transfer conveyor stops moving.
Shrink Tunnel Adjustments
By this time, the machines should be off the pallet, with the correct electrical supply, film rack installed, film properly threaded, the sealer set, and the transfer conveyor stopping when products reach the front of the shrink tunnel conveyor belt. Most shrink tunnels will have conveyor belt settings, with temperature settings, and higher-end models will also have blower motor adjustments.
Set the temperature to 300 degrees Fahrenheit and allow the tunnel time to warm up. The conveyor speed should be set in the middle of the available settings. If the high-end rate is ten, begin with the conveyor set to a five. If a blower motor setting is an option, we recommend a medium setting to start with that as well.
Run a product through with the tunnel conveyor and blower motor settings midway and the temperature set at 300 degrees Fahrenheit. Make a seal and let it go through the shrink tunnel. If the product exits the tunnel with minimal shrinking, increase the temp to 325 and try again. If the product leaves with noticeable shrinking, but not enough, slow down the tunnel conveyor. It is essential only to make adjustments to one setting per test run. It will allow you to dial in the machine faster.
Read our recent troubleshooting post if you have difficulty attaining the correct shrink rate. Once the combo system is adjusted to the proper settings, workers can turn on the machine, allow time to heat up, and go to work.
Auto Shrink Machine Set-Up
Due to the numerous fully automatic machines available, we will not be able to provide a setup guide. There are too many working parts and adjustments that need to be made. We highly recommend a trained technician installing a fully automatic shrink wrap machine. Below are some general aspects to consider if you are interested in buying a fully automatic shrink wrap machine.
Most automatic shrink wrap machines will be either one or two-piece machines. A one-piece machine will have one plug powering the sealer and shrink tunnel. These are often lighter-duty automatic shrink wrap machines for small products. For more oversized products, a two-piece automatic system would be recommended. The shrink tunnel and sealer would each have separate power supplies. Larger heat tunnels require a fair amount of electricity to maintain temps.
In addition to the automatic sealer and tunnel, you will need infeed and exit conveyors. They will transport products into and out of the machine. Powered conveyors are necessary for the infeed, but a gravity roller could be used for the exit. Some products will work best with a flighted conveyor for the infeed conveyor, which helps keep products separated. The most common infeed is a standard belted conveyor with adjustable speed. Many machines also have conveyors that sync with the machine speed during production.
Once the suitable machine and conveyors are determined, you will need to look for a crosslinked shrink film. Most automatic machines use a hot knife sealer with temperature adjustments. Crosslinked polyolefin shrink film runs best with these sealers because of its heat tolerance and stronger seal strength. The cost is slightly more than standard shrink film, but the quality with worth the increased price.
Be sure to inquire about the following setup options for an automatic shrink wrap machine:
- Add-ons - Conveyors or labelers to go with the machine.
- Shrink Film – Be sure to choose a shrink material that will run on the machine. Standard polyolefin shrink film often does not work well.
- Parts – Are parts readily available for the machine?
- Shipping and Crating Options – How is it shipped and crated, will forklift extensions be necessary?
- Electrical Supply – Ensure the proper electrical hookups are ready for the machine.
- Onsite Set Up – Is a technician available for set up and training.
Once an automatic shrink wrap machine is set up and running, employees can be trained on operation and film threading. Adjustments will need to be made for different product sizes, but minor adjustments are easy to make once instructed.
People are often concerned about shrink wrapping setup because it does have a slight learning curve. As machines increase in efficiency, they increase in complexity. Following the instruction manual specific to the device being set up is the best option; if that is not an option, we hope this helps explain some setup options for your heat shrink wrapper.