As a manufacturer of inline capper and chuck cappers we have dealt with thousands of different bottles and caps and the reality is that capping is one the hardest part of of the bottling process.
The main factors to take into consideration for better bottle capping results are:
Choose the right Type of capping machine
Inline cappers: This machines have the benefit of costing less, not needing change parts and being able to handle a wide range of caps including trigger sprayers (placed by hand). The main issue with this machines is that there are bottles and caps that have the tendency to cross thread, and difficult caps and/or bottles will have more issues on an in-line machine than a pick and place capper. Mots companies run this machines up to 100 bpm (bottles per minute) but some can run up to 250 bpm (depending on the bottle and cap design)
VIDEO INLINE
Pick and place chuck cappers: This machines work better on most containers and caps because the cap is transferred to the chuck and once it’s on the chuck it’s placed controlled, straight onto the container. If you pick the cap with the bottle
you have the threads of the container picking up in different random positions so if the tolerances and/or the design is a bit tight or not forgiving you get cross threaded caps.
This type of machines work great but have a high cost and require change-parts for each additional bottle and cap adding to the already high cost.
For speeds above 200 bpm it’s the only effective solution
VIDEO CHUCK
Cap - bottle thread design
Cap design: The cap design is critical, before you commit or buy large quantities make sure everything has been tested with your machines in your production floor. We’ve done projects where with the one bottle one cap we got 5% cross threaded caps and a different design, same sizes, we got 0.2% cross threaded caps
The design of the bottle it’s also very important as well as the tolerances, specially with glass bottles. Also there are Designs that the thread on the bottle begins in the top edge and others have a small gap, on an inline machine this makes a big difference because when you pick the cap, if you have space the cap can sit properly before starting to thread
Keep in mind each bottle and cap needs to be looked into, studied and tested to make sure it will work properly for your required speed, torque and consistency.
Isaac Possin
Author