Hollow glass production cycle



    Shears
As the stream of molten glass leaves the melting tank, it is cut into gobs by automatic mechanical shears. Both lubricant and cooling are needed here, and these are provided by Renite D-5-A shear spray concentrate, diluted with 300 parts of water. This spray concentrate will perform ideally on most applications. For special needs, high-quality, quickly biodegradable spray concentrate for shears is also available (Renite D-9) along with a clean, synthetic, animal/vegetal/mineral-oil-free spray concentrate (Renite Syn-Cut SC-3). This spray concentrate is applied with the heat-resistant, all-metal Renite E model atomizer, which delivers a very fine, precisely controlled spray. Also effective and useful for this purpose is the special Renite Extension Head atomizer that allows nozzle-positioning closest to the blades with valve block "extended" or removed a distance from the extremely hot area.
 
 
    Chutes, troughs and deflectors
Next, the gob travels to the blank mould through a series of chutes, troughs and deflectors.

Renite Slide D-10, a two-component graphite/epoxy coating, is applied to these to provide a heat- and moisture-resistant surface with good lubricity. The components, in convenient-sized packages, are blended together just before use and applied with a brush. The coating hardens in about six hours, without need for oven-curing. Please ask for samples to try the newest Renite Slide D-20, an evolution of the D-10, which will consist of a single product, apply with a brush and any temperature.
 
 
    Blank mould area
In the blank mould, the gob is pressed or blown to form a parison, a hollow miniature container with thick walls which will later be blown in the finish mould (blow mould) to final shape. This is the most difficult stage of the forming process, and correspondingly, the blank mould lubricant is the most important lubricant in the forming sequence. At this stage a special swab lubricant is recommended, such as Renite F-72 (general purpose and heavy-duty) and Renite F-95 (lighter and cleaner for applications such as pharmaceuticals and cosmetics), both featuring such a viscosity to avoid any dripping or leaking.
A lighter and cleaner product is also available, Renite H, which can be swabbed or automatically applied with the heat-resistant, all-metal Renite E model atomizer.
In the blank mould area, excellent performance is furthermore granted by Renite CH, a light-duty swab lubricant recommended for the production of blue, yellow and black cosmetics ware. It is also recommended for press moulds, with considerably less fumes than Renite H.
 
 
    Precoating of blank moulds and auxiliary equipment
For lubrication of blank moulds and auxiliary equipment on the newer machines, there is a trend in preference toward lighter and cleaner lubricants. Renite has responded in part by formulation changes and use of modern dispersing and blending equipment to give a more homogeneous product.
In addition, Renite now offers its precoating,
Renite R-Seal AKX, which is applied to blank moulds and auxiliary equipment before they are put in service.
The coating, water-based, is applied like a spray paint. Preheating before application or oven-curing afterward is not necessary; it dries in a few minutes to form a hard, durable coating which can take the normal handling involved in putting the equipment on the machine. Presently, with use of
Renite R-Seal AKX, it is possible to go two hours without swabbing at start-up time, a very busy time for the operator.
After that, swabbing begins, but frequency of swabbing is less than without the precoating.
Typically, a plant will use about a third less blank mould swabbing compound after adopting the
Renite R-Seal AKX.
More important to the operators, is the reduction in aggravation and smoke that results from less need to swab. Better distribution and greater cleanliness of ware and equipment are extra bonuses.
 
 
    Neck rings and other auxiliary equipment
In addition to the blank mould, auxiliary equipment used in formation of the paraison - neck rings, bottom plate and plunger - also needs lubrication. The blank mould lubricant is sometimes used for these, but usually a more fluid and lighter lubricant is preferred for the neck rings. The best product for this lubrication is Renite H-9.
In addition, where special cleanliness is needed, as in manufacture of baby food and mayonnaise jars, some use Renite H, a lightly graphited oil that has been used since the earliest days of the company for manufacture of fine quality pressware. Renite H has been updated by a switch to a cleaner oil and to a grade of graphite so fine that it remains in indefinite suspension without the aid of a thickening or suspending agent.
 
  
    Finish mould area
Continuing on, the paraison is transferred to the finish mould for final blowing to shape.
Not much lubrication is needed here, but a light touch of lubricant often helps. The previously mentioned lightly graphited oil, Renite H is sometimes swabbed on finish mould shoulders or bottom plates, as is Renite F-5, the lightest of Renite's earlier blank mould swabbing compounds. Renite also offers special anti-check pastes that are applied trouble spots on finish moulds, the most popular of these being its low-sulphur paste, Renite Chek-No Mor.
 
 
    Precoating of finish moulds
Renite LMP, MP e MPR are used for the precoating of finish moulds in the manual production process, on Hartford 28 or similar equipment. These products are applied with a brush, delivering a sticky precoating able to capture cork or saw dust. The oven curing will then harden this precoating, which is afterwards mildly rubbed and moistened.
 
 
    Lehr mat
Finally, the finished container reaches the lehr mat, where it begins its trip through the annealing lehr. To largely eliminate bottom checks and rust pick-up during this trip, the mat may be coated with Renite S-24, a water-based graphite concentrate applied by spray or roller, or a simple trough-and-roller arrangement which is placed against the mat at the floor near the hot end where the mat enters the lehr.
At this point, the mat has cooled somewhat, but is still warm enough so that the coating dries before it contacts the ware.
Diluted about 5:1 with water, the Renite S-24 is thus applied automatically in a short time as the mat travels by, one application being suitable for several days of operation. Operators also make an "S-24 Goop" by blending Renite S-24 with an equal volume of flour.
They claim this makes an excellent and long-lasting coating for take-out tongs, star-wheel paddles and other such tools that contact hot glass.
 
 
    Chullet cute
With Renite lubrication from shears to lehrs, quality will be good and percent pack high, but due to mechanical and other problems, some of the glass will end up as cullet.

Renite eases the trip down the cullet chute wi
th Renite BL-1-B, its water-resistant cullet chute grease.
 
 
    Other opertaions – Special services
Renite, in addition, has a full range of lubricants and spray equiprnent for glass-forming operations that do not involve IS machines, including manufacture of pressware and hand blown ware, Hartford 28 operations, and glass sagging.
Do not hesitate to contact us for any further information you may need with this regard.

 

Metal Working

Top

Hollow Glass Production