ドリル加工の代わりのフライス加工

穴あけ加工の最速の方法は、適切なドリルを使用することです。材料に円形に入る直径の小さいフライスカッターは、加工中にかなり長い距離をカバーするため、サイクルタイムが長くなります。しかし材料によっては、ドリルの時間的優位性を打ち消すような非生産的な時間が発生することがあります。

e-モビリティへの移行の過程で、切りくずの長いアルミニウムからなる溶接設計や構造部品が機械加工されることになります。 たとえば、バッテリーのハウジングは、シリコンをまったく含まないか、またはごく少量しか含まない押出成形品から作られることがよくあります。 そのため、切りくずの破壊がより困難になり、切りくずの巣ができ、機械や工具に引っかかる可能性があります。 鍛造アルミニウム製のシャーシ部品を加工するときにも同じ問題が発生し、メーカーも長い切りくずに悩まされています。 工具のシャンクに付着すると、自動工具交換ができなくなる可能性があります。 切りくずクラスターは中断を引き起こし、加工時間に悪影響を及ぼします。

Especially during drilling from solid or certain boring operations, a burr can form which is pressed out and wraps around the tool as a ring. “These rings accumulate at the tool cutting edge and can damage the workpiece and the tool”, confirms Leander Bolz, Sales Manager of PCD Tools.

In principle, drills can be equipped with chip breakers, but these usually impair the tool life. In addition, with the materials used, it is not always guaranteed that the chip breaker will reliably do its job. Aluminium with a low silicon content can display different properties depending on cast, batch or the storage condition, which is also reflected in different chip formation. This means that in practice the stock removal situation of the pre-machining is often changed. While blades or entire tools sometimes have to be replaced with a drilling tool, the stock removal with a milling cutter can easily be reduced or increased via the driven tracks.
 

The milling strategy also demonstrates its flexibility when bores with different diameters are required. A single milling cutter can be used for this. For larger bores, it eliminates the need to replace one or even two drills for pre-machining. MAPAL favours using the milling cutter for the materials in question since it is possible to save time, particularly during pre-machining, which outweigh the initial performance disadvantages compared to drilling. For certain workpieces, the milling cutter is superior from the outset, for example when there is a risk of deformation due to drilling thin walls of structural parts or when bores with a very specific roughness are required in chassis technology.

Combination tools further reduce the cycle time, as Leander Bolz explains: “If the milling operation sits at the front of the tool and the fine machining behind it, the bore can be created completely in one pass.” With various geometries to choose from, the tools are adapted to the respective machining operation. MAPAL offers SPM milling cutters (Structural Part Machining) with PCD cutting edges for machining aluminium. These very sturdily designed high-volume milling cutters were originally developed for the aerospace industry to machine material from solid.