11.05.2023

A strategy for battery frames

The complete machining of parts has to be well thought out, every step coordinated with the next. This is the only way to attain reliable and cost-effective manufacturing with perfect results. To provide customers with such sophisticated strategies, MAPAL has defined focus components on electric cars and worked out the optimal machining strategy for them. The battery frame is one of these components.

#Produtos #Industries #Automotive #E-Mobility #Milling
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    The solid carbide milling cutter OptiMill-SPM-Finish finishes large pockets in a single pass. ©MAPAL 

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    The generic component presents the challenges involved in machining a battery frame. ©MAPAL 

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    The specially designed PCD milling cutter machines both bores with different diameters. ©MAPAL 

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    Took an in-depth look at battery frames at MAPAL and their optimal machining strategy (from left to right): Andreas Wolf (Test Engineer), Florian Hofmeier (Component Manager Driveline) and Michael Kucher (Component Manager E-Mobility). ©MAPAL 

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    In total, seven tools are employed by the generic process to machine the battery frame. ©MAPAL 

The battery frame is a crucial part in every electric car. It usually consists of various frame elements that are welded together after pre-machining and act as the battery’s enclosure. Based on various customer parts, MAPAL’s electric mobility experts have put together a generic component that encompasses the main machining operations of a battery frame. “With this part, we highlight the special challenges involved in machining”, says Michael Kucher, Component Manager E-Mobility at MAPAL.


The challenges faced while machining the part include stepped bores, bores with different diameters through multiple layers, milled pockets with varying dimensions, shoulders, and high demands on the resulting surface.

The generic component presents the challenges involved in machining a battery frame.   ©MAPAL
“We master these challenges above all with the optimally designed milling cutters”, says Kucher. Milling is even used for most bores on the frame part. Depending on diameter and machining depth, the experts decide in each case whether to drill or mill. “While the cycle time during the milling of bores is somewhat longer, milling offers decisive advantages in this case, which more than make up for the lost time.” In the past, long chips which occurred while drilling aluminium parts often proved very problematic to customers. “Removing long chips from inside the frame part presented a risk for the process”, says Kucher. The short milling chips are easy to remove. There is also a lot less burr formation during milling than drilling. And there is no need for tools changes. Multiple bores with different diameters can easily be machined with a single milling cutter.

This advantage is brought to bear particularly when a bore has a larger diameter in one of the lower layers than the bore entrance at the top layer. “This can be done effectively with a reverse cutting edge on the milling cutter”, says Kucher. The alternative would be reclamping the workpiece in order to machine the bore from the bottom with a drill. A specially designed PCD milling cutter from MAPAL machines the bore at a spindle speed of 16,000 rpm, a cutting speed of 650 m/min and a feed of 0.063 mm.
 
In total, seven tools are employed by the generic process to machine the battery frame  ©MAPAL

OptiMill-SPM-Finish による最適な表面仕上げ

マパールでは、ポケットの仕上げ加工だけでなく、ショルダー、ポケット、スロットの荒加工にも OptiMill-SPM-Finish を推奨しています。 「最適な表面仕上げを実現し、大きなラッピングや高負荷がかかるコーナーでも安定して動作します」と Kucher 氏はこのツールについて語ります。 フルートを研磨しているため、切りくず排出機能も万全です。 このツールの特別な特徴は、 1 回の加工パスで大きな切込み深さできることです。 これにより加工時間が短縮され、生産コスト効率が良くなります。 バッテリーフレームの仕上げでは、最大 Rz = 1 µm の表面仕上げが達成可能です。 荒加工中は、主軸速度 10,981 rpm、切削速度 414 m/min、送り速度 0.12 ～ 0.22 mm で動作します。 送り 0.075 mm で仕上げ加工を行う場合、同じ主軸と切削速度が達成されます。

一般的なプロセスでは、OptiMill-SPM-Finish のほかに、新しく導入しました FaceMill-Diamond-ES など、6 つのフライス カッターを含む合計 7 つのツールが使用されます。 完全に調和したシステムを実現するために、円筒シャンクを備えたすべての工具は、UNIQ チャック（ハイトルクハイドロチャック）に保持されます。

「当社は現在、PCD および超硬工具、チャック、および対応するプロセスを含む、バッテリーフレームの機械加工の課題に対応するための包括的なパッケージをお客様に提供できるようになりました。 このため、私たちはお客様の具体的な状況に基づいて一般的なプロセスを適応させます」と Kucher 氏は説明します。

MAPAL solutions for electrified mobility
Kathrin Rehor, PR Project Manager at MAPAL

Contact

Kathrin Rehor Public Relations Kathrin.Rehor@mapal.com Phone: +49 7361 585 3342

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