|
|
 |
|
 |
|
|
|
 |
|
 |
You are here  PRODUCTS Plastics Processing
|
|
|
 |
|
|
|
|
|
|
|
Cutting in plastics
Machines
Ordinary cutting machines for metal or wood processing can be used. The latter as well as CNC controlled machines have the benefit that they can run with high number of revolutions.
Tools |
|
|
| |
|
The standard tools most suitabel for cutting in plastics is aluminium cutting machines or cutting machines for woodworking. Regarding shape and range of application the tools can be divided into a large number of types, eg. cylindrical cutter, shell face mill, saw cutter, side milling cutter, cutter or inserted blade cutter. Usually, the tool material in the cutters is High Speed-steel or hard metal. The High Speed-steel is easily shaped and for this reason a large number of milling tools and especially tools with small dimensions are made of this material. Single-fluted milling cutters or bits with steel milled as specified during turning is the ideal and should be used when the aim is fewest possible tensions. |
|
|
| |
|
Double-edged cutters are often used at closed flutes and key slots, as you in contrast to four-edged cutters avoid packing of the material. Shell face mills are especially used at larger surfaces and works involving strong cutters on a short end mandrel. Side and face cutters with staggered teeth will be used for deep flutes, especially in soft materials like plastics. |
|
|
| |
|
The conditions for rational cutting are:
- High cutting speed
- Sharp tools
- Powerful cooling
- Rational set-up
It is important to avoid:
- Growing chips
- Sharp crossings
Cutting Speed |
|
|
| |
|
When cutting plastics the cutting speed must be high.
The formula used for turning can alos be used here.
V = D x n / 320 or n = V / D x 320
V = Cutting speed (m/min.)
D = Cutting diameter
n = Number of revolutions per min. |
|
|
| |
|
St-Up
It can involve problems to set-up items on the milling machine table. Soft materials to be cut into thin items give problems with the positioning of the locking elements. Be sure to lock as close as possible to the tooling place and take care that the item cannot bend during the tooling process. Continously make sure that item did not come loose. Vacuum plan is a good solution as it provides the possibility to cut the entire outer edge in one set-up. This also allows the item to extend lengthwise in case of increase in temperature.
Most types of plastic are insufficient heat conductors. If we imagine a sheet as shown in the figure to be cut on the top face, an increase in temperature due to the cutting will result in a lengthwise expansion. The setting and the expansion will make the sheet curve. Hereby more than intended will be removed from the curved part and the result will be as is seen at the bottom of the fgure. |
|
|
| |
|
Feeding
At cutting feed per tooth is used. The feeding is calculated as follows:
St = Sb / t x n
Sb = feeding of table (mm/min.)
t = number of teeth on the cutter
n = revolutions per min.
Feeding per teeth when cutting plastics (St) (approximate) |
|
|
| |
|
|
|
|
| |
|
Table cutting data
Approximate cutting angles, speed and tightening values for various materials are available in the below table.
|
|
|
|
|
|
|
|
 |
|
|
Vink Holding B.V. · Oude Utrechtseweg 26-28 · NL-3743 KN Baarn · Phone +31 35 53 99 888 · Fax +31 35 53 99 870 · info@vink.com
|
|
|
 |
|
|
