SHINKOLITE L continuous cast sheet can be cut, machined, cemented, painted and printed very easily, using the same techniques used for conventional glass cell cast sheet, conventionally cast sheet in most cases. Although the same forming methods as cell cast sheet is applied, SHINKOLITE L has significantly better thermoformability than conventional glass cell cast sheet and can be formed to greater detail at shorter cycle times.
(1) Cutting
SHINKOLITE L can be cut, drilled, scraped, engraved and machined with conventional equipments and techniques, however, in order to prevent excessive heat accumulation it is recommendable to put wax paper or polyethylene film in between the sheet and always blow off sand dust when cutting or drilling stacked sheets. For cutting, circular saw, belt saw, scroll saw, jig saw, router, razor light ray are used.
- Circular saw cutting
Mostly used for rectifineal cutting. Chip saw which has long life is ordinarily used. Conductions for saw and cutting are as follows.
Opening 150~350mm opening should be larger as the thickness of sheet becomes thicker. Trimming width 2.6~3.0mm Teeth 2.5~3.0 set/inch Operating r.p.m. 3,000~5,000 r.p.m. Saw speed 2,400~3,600 m/min. Feeding rate 3~7 m/min. if too fast, chipping on the cut edge
if too slow, sticking or gumming.
- Belt saw cutting
Used for moderate curves and trimming of molded product. Compared with circular saw, condition of cut end and cutting speed is not as good. The following conditions are given below.
Thickness Teeth Saw Speed 1.5~3mm 14/inch 1,500m/min. 4~10 10 1,000 13~30 6 700 - Cutting with scroll saw
Curve cutting and plate-cutting-out can be done but, compared with other kind of saws, sectional heating occurs easily. Use rough-teeth saw according to thickness of the sheet, e.g. 2mm --> 15/inch, 5 mm --> 9/inch, 10mm --> 7/inch.
(note) When cutting piled sheets, it is effective to place polyethylene film in between the sheets or to put wax onto the parts to be cut in order to prevent gumming.
- Jig-saw cutting
The machine itself is compact and portable, with an advantage of easy curve cutting but cut end is a bit rough and necessitates finishing.
- Router cutting
This is used for trimming of curve cutting, cut outs and for processing of taper edge. Compared with scroll saw and jig-saw, it is efficient for fine-cutting. When cutting larger amounts of same shaped products, NC-automatic cutter is available.
- Razor light ray cutting
This is very efficient with satisfactory cut ends and automation is possible but machine is rather expensive. Through heating, inner stress is generated near the cut area, which causes cracking when cemented or coated.
(2) Drilling
Ordinary drilling machine or portable electric drill is used. Following blade is recommendable.
| Angle Θ | 120~140° | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Angle δ | 10~20° | ||||||||
| Feeding speed | 60~300 mm/min. | ||||||||
| Operating r.p.m. Diameter |
|
Heat transmittance being small, sectional accumulation of heat may occur easily.
Rise in temperature should be kept minimum by blowing air or by dripping soap water.
Right feeding speed should be kept, not to cause chipping by high speed, not to generate gumming by low speed.
Saw dust initiates heat generation and hinders cooling, so when the desired hole is deep, frequent cleaning of the drill is necessary.
(3) Other machining
Besides the above, processing by screw cutter, lathe, milling machine, engraving machine and planning machine can be done. Followings are the common points to be remembered.
- Stabilize firmly the product to be processed in order to avoid deformation at time of processing.
- Pay good attention to the quality of the machine whether blade is sharp or blunt.
- Select appropriate feeding speed.
- Keep both processed parts and the machine constantly cool.
- Always clean saw dust and shavings.
(4) Polishing
When the surface is rough, for instance cut edge by
saw, plane and/or sand the surface to smooth out the
surface.
When sanding, use water resistance paper #600~#1500
in graduation from coarse to fine. Finish by polishing
with abradant using a soft cloth.
Finishing can be done by buffing.
Buffing speed is approximately 1,100~1,400 r.p.m. (buff
speed should be 700~1,500m/min.) and abradant is jointly
used. If buffing speed is too high or if buffing is
placed at one part, sticking or inner stress can be
generated by heat.
Scratch is eliminated according to its depth, by sanding
and buffing or by buffing alone.
(5) Flame polishing
Hydrogen and oxygen are mixed, blown and combusted through a small nozzle. The flame is used for polishing, which makes surface semi-smooth. This is efficiently used for edge surface polishing.
Prior to flame polishing, rough surface should be planed or sanded.
Shifting rate of the flame should be about 6m/min., the slower the rate, the more satisfactory smoothness is gained but if the rate is too slow, bubbling occurs. Because inner stress remains in flame polished area, cracks may appear if cementing or painting is done.
(6) Cementing
SHINKOLITE-L can be easily cemented with appropriate organic solvent or polymerizing adhesives. The following are roughly grouped adhesive that can be applied.
- Type 1. Solvent:
- Methylenedichloride, or mixture of methylendichloride and glacial acetic acid.
Adhesion is extremely easy and adhering rate is very high.
Adhesive strength and outdoor durability are comparably unfavorable. - Type 2. Solvent+Polymer:
- To the above solvent, a small amount of methyl methacrylate polymer is added and dissolved.
- Type 3. Syrup+Hardening agent:
- To partially polymerized methyl methcrylate syrup, initiating agent for polymerization (hardening agent) is added. Cementing is done through polymerization. Firm cementing by filling the space is obtainable but adhesives should be prepared every time of the use, its life time is rather limited and curing time is rather long, which are the demerits of this type.
- horizontal cementing(1)
- horizontal cementing(2)
- joining face to face
The following are points to be noted for adhesion.
- Mask parts according to necessity, to avoid adhesive from sticking to the parts other than the adhering area.
- Thoroughly wipe the adhering surface.
- For type 1 cementing, injection, for type 2 cementing, oiler or eye dropper is generally used. For type 3, make an applying opening and directly pour adhesive into the space. For this type, cover the upper surface with cellophane or polyester film in order to keep oxygen absorption as minimum as possible, until polymerization is completed. (Oxygen absorption hinders polymerization).
- Do not move it until firmly adhered. All the volatile matters should be sufficiently evaporated, after adhesion. Defects at time of cementing and its prevention are as follows.
- Crack, Craze
- Occurs when there is larger stress from outside and comes in contact with adhesive.
- Occurs when there is inner stress generated during the pre-processing stage or when water absorption is large. It is necessary to control these stresses not to concentrate only on certain area.
- Bubbles
- Bad setting of adhering surfaces.
- Too fast evaporating rate of adhesive.
- Bad injection of adhesive.
- Insufficient pressing power.
- Too fast polymerization of adhesive or partially different reactive rate.
Bubble defects can be attributed to the above causes. Evaporating rate can be controlled by changing mixing ratio of methylenedichloride and ethylenedichloride, and also by mixing high temperature boiling point solvent to methylendichloride.
- Haze
When air temperature is high, parts in contact with solvent tend to haze due to condensation of vapor which happens with evaporation of solvent. This can be avoided by reducing evaporating rate. Also it is effective to add small amount of water solvable high temperature boiling point solvent (5~15%) such as diacetone alcohol, glacial acetric acid.
Compared with conventional glass cell cast sheet, dissolvement or swelling rate of SHINKOLITE-A L by solvent is slightly faster.
(7) Thermoforming
Compared with cell cast sheet, SHINKOLITE L is easily formed. Besides strip heating, SHINKOLITE L can be heated by normally air oven and infrared oven. Like all acrylic sheets, when heating SHINKOLITE L heat must be dispersed uniformly over the entire sheet and because of its good thickness tolerance, excellent result can be obtained. Conventional thermoforming equipment is used for SHINKOLITE L and normal forming technique can be applied. Recommended forming temperature range for SHINKOLITE L is 135°C~175°C (275°F~347°F), approximately 5~10°C (9~18°F) lower than that of conventional glass cell cast sheet. Such wide range and good thermostability not only makes forming easy but shows excellent deep draw formability. When SHINKOLITE L and S, with identical thickness, heated under same temperature are formed, compared to conventional glass cell cast sheet, SHINKOLITE L yields products with much sharper detail. This means that SHINKOLITE L require a shorter cycle time to form than SHINKOLITE S, this deducing forming costs. The details are shown in Figures 1 and 2.
(8) Painting
SHINKOLITE L can be painted with the same paints, techniques and equipment used with cell cast sheet.
Please click the button and download
the latest to view PDF files.
