Working on a project currently and would like to incorporate a semi-opaque ‘window’ into an opaque shell, similar to the way some oil bottles are done so you can see how much oil is left. Is anyone familiar with how that is achieved? thanks
A guess: In the blow-molding process the material hopper is separated into two compartments that lead all the way to the nozzle. Simply load one compartment with a translucent material and get a “stripe” of translucent material extruded as a result–which is then inflated into the bottle-shaped mold. This means that the stripe will be imperfect, and run the entire length of the bottle.
An alternative method to give you more control of the window might be to use translucent material but use in-mold decoration or a heat-shrink wrap.
thanks a bunch cg, another question if you’ve got time
how would in mold decoration affect recycle-ability?
I’m no pro with plastics, but when you re-grind them they typically end up with one color as if you’d mix every color of paint in the spectrum together, unless the colors are separated before the re-grind. In your case the one solid color plus the one translucent color would end up the same color if it was separated from other plastics before the re-grind process. This scenaro would only happen in a perfect world where plastics are separated by color.
Sorry it took so long for me to see your post.
No, the materials are not seperated in the hopper!
Visi-Stripes are produced by feeding natural P.E. into the side of the head in the area where the parison (tube) extrudes from the head.
With some clever design this stipe could be widened to a ‘panel’
The stripe is usually continuous - not turned on and off.
If this project is still of interest please contact me.
robin@bmc-controls.co.uk
regards,
Robin Enderby
recycle-ability is often a goal not a mission…
Until it is a decree the mass market is not yet willing to take the yellow milky bio plastics and neither is your dishwasher. Let me restate what we know about the design process and remind us all about making concessions and compromises. Designers typically have to compromise too much when specifying recycled materials and so does everyone else.
I look at it like this. Marketing, design and engineering all have their primary and secondary wishes for a final product. Color, texture, structure with respect to stress and strain (FEA), warpage, moldability, Drop testing (ability for the product to withstand extreme cold and heat form…
The primary mission for a product needs to be recycle…
then all the other wishes must be dealt with or compromised depending upon the language you choose. A recycled material will not have that perfect red for example so marketing might be persuaded to comprise. (thats a Marlboro red not a Target Red one day and different an another run)
The recycled material may not be easy to guess its exact material composition therefore it is difficult to guess it’s structural integrity. Engineering must now be persuaded to compromise.
The Recycled material may have a problem with extreme cold and crack when drop tested. To solve the problem industrial designers might have to compromise on shape.
The recycled material might have a problem with extreme heat and have a tendency to warp. The Industrial Designers and engineers might work out a n idea to adjust the form so the part will warp in only one direction but that affects the form slightly so the ID is forced to concede some on form.
And no one on the team will budge. What do you do? You start talking and persuade each spoke on the wheel to make cons sessions or someone with the power tells you to shut up and the products material goes virgin. Virgin material with no regrind goes on the note and our ideal for ‘recycle’ is out the window with all the other ideals.
If you have a champion or a buyer who dictates the product must be recyclable like we are seeing at Walmart and Target now… We start to see those compromises tinkle down and everyone has to swallow the compromise.
to answer your question the recycled product with the clear polyethylene window/stripe will not be easy to recycle into one category ?? Both might go polyethylene then yes … Otherwise the dead product when recycled goes into the bin called OTHER. You might ask marketing to compromise in favor of recycling and loose the window. I also suggest pushing your molder with these concerns and questions.
They can solve, educate and understand many issues… Robin? Comment/