Before buying a CNC portal milling machine: Please inform yourself in our FAQ field! Here you will get advice for often appearing queries.

• CNC machine purchase: What do I need for a start?
• Table grooved: What is the difference between the 15mm and the 20mm profile?
• Vacuum technology: What is recommendable?
• Stepping or servo motors? What is recommendable?
• Software for the machine controls: What is recommendable?
• Software for CAD, producing of drawings: What is recommendable?
• Digitising of work pieces: What does that mean?
• Operating time of milling spindles: What has to be considered?
• Milling spindles with automatic tool change: What has to be considered?
• 4-axis: With worm gear or Harmonic Drive gear?
• Composition: Which components are suitable for my needs?
• What does BZT mean by saying spindle-set and why is the first mentioned article, which is optically similar, cheaper?
• The Ebay offer in the illustrated form does not suit to my needs? What can be done?
• Which components belong to the scope of delivery?

CNC machine purchase: What do I need for a start?

• A CNC milling machine,
• Table grooved or vacuum table incl. pump or lateral canal consolidator
• CNC control as a stepper od servo design
• Milling spindles, performance according to the use with 2.2 KW for example, rotation speed 24000 rpm for example, optionally with or without automatic tool change. Then you also have to decide for a clamping system. There are available for example the SK20 or the newer HSK E-25 system.
• Software, for controlling the machine, for example WinPC-NC, Mach 3 or our BZT SB control
• Software for transforming drawings, for example DXF, Stl etc. into a CNC code, which can be read by the control (DIN code)

T-Table grooved: What is the difference between the 15mm- and the 20mm- profile?

The 15mm T-Plate grooved consists of a drawn 15mm aluminium hollow section profile (cheaper but more inexact). On the opposite, the 20mm grooved plate consists of a massive profile, what afterwards is face milled and only later is anodised (extremely precise). The difference can be explained with the following photo:

Vacuum technics: What is recommendable?

It is always difficult to recommend something, it has to be tested in practice.

For millings through in huge amounts a lateral canal consolidator with 2 levels is recommendable. It has a big air volume and a higher low pressure than a lateral canal consolidator with only one level (advantage: cheap, disadvantage: relatively loud)

Vacuum pumps are better: They have a high low pressure, but not such a big air volume.  Then with many or very big millings through the vacuum can break down very fast  (advantage: very calm, disadvantage: very expensive)

Stepping or servo motors? What is recommendable?

The stepping motor is the cheapest approach of moving a machine. The control sends an impulse and the step motor makes a step, for example 1.8 grades (with 360 grades with 200 steps per rotation the machine processes 1.8 grade per step. For a spindle with an ascent of 5mm it would be 0.025mm). The costs per axis are ca. 150.00 €. The big disadvantage of the stepping motor is the maximum rotation speed of ca. 1,000 rpm and the open control circuit, as there does not exist a recirculation of the impulse.

The servo motor is a motor with a sensor system, which in connection with the servo controller carries out the impulses and via the sensor system also controlls, if these impulses really have been carried out.  The big disadvantage of the stepping motor is the high price of ca. 2,000.00 € per axis, but for this high price you get a highly dynamic system with up to 6,000 rpm.

Software for machine controls: What is recommendable?

Mach 3: by BZT with an own surface, ease in operation, can be compared with a right CNC control by Siemens and Heidenhain. Only via a LPT interface, further programs on the PC cannot be run.

WinPC-NC: ease in operation for someone who, for example, knows Corel well. The surface cannot be compared with the right CNC controls.

BZT-CNC USB: very clean surface, ease in operation. It is very close to a right CNC control by Siemens and Heidenhain. It runs very reliably by using USB.

Software for CAD for compiling drawings: What is recommendable?

CAM, it produces CNC programs for the machine control from drawings.

Digitising of work pieces: What does that mean?

If work pieces are digitised with a feeler, for example with Mach 3 or BZT-CNC for USB, there will be produced a point cloud.

This point cloud consists of incoherent x, y and z coordinates, for example with a further software (for example Rhino CAD). It can be transformed to a closed surface and then it can be stored in 3D format under STL. When now this STL file shall be milled, a further program is needed

(for example Cut 3D) for transforming this file into a program (G-code), which can be read by the CNC control.

Operating time of milling spindles: What has to be considered?

Kress. max. 1 to 2 hours per day. BZT KTE219
Suhner max. up to 4 hours per day. BZT KTE900
1.0 KW HF spindle incl. converter up to 8 hours per day. Cheap HF spindle, a speed regulation is only possible at the Poti at the spindle. BZT KTE325-S
BZT 1.0 KW HF spindle incl. converter up to 8 hours per day. The speed regulation takes place via the machine control software. Very comfortable!!  BZT KTE611-S-IP54

Milling spindles with an automatic tool change. What has to be considered?

It has to be mentioned that there are different performances and rotational speeds. We can offer spindles from 1.0 KW up to 15.0 KW. But nowadays more important are the clamping systems. There used to be only SK20, SK30 or even SK50 for example. In these days the HF spindles have a  HSK clamping system, which has the big advantage that it does not only have a cone but also a planning system and thus it tenses extremely better and more stable. Nevertheless, spindles with tool change always need a machine with a control cabinet, as diverse electronic parts, like for example standstill controller and contactors, have to be built in in order to guarantee a smooth tool change.

4. Axis: With worm gear or Harmonic drive gear?

The most 4-axis with stepping motor and worm gear are totally easily constructed and have relatively a lot of play (reverse play) – the costs are ca. 1200.00 € incl. lathe chuck with 100mm. Harmonic Drive gears are the only gears without play worldwide. They are very precise and have repeat accuracies of only a few seconds of arc. The disadvantage is that they are very expensive. All 4-axis incl. lathe chuck with 100mm cost about 2,500.00 €

Composition: Which components are suitable for my needs?

Please ask by mail by indicating your postal addresss (particularly for machines please indicate your telephone number, too) and possibly the offer number from Ebay. As an existing customer please tell us your customer number, so that BZT can collect fast all information necessary for an offer. You can reach our sales team by This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

In case of doubt please speak with our sales department by dialling 0049 05202 9930686.

What does BZT mean by saying spindle-set and why is the first mentioned article, which is optically similar, cheaper?

Normally we first mention the spindle as a single part.
Our sets serve as an upgrade of BZT machines and therefore it normally entails many parts, for example frequency converter, cable, assembly, installation, pneumatics, adapter plate, cap nut etc. – Example: Customers who use a Kress motor and want to upgrade to a 1KW spindle can see the correct price immediately.

The Ebay offer in the illustrated form does not suit to my needs, what can be done?

Our sales team will answer your questions by mail. Please ask by mail by indicating your postal addresss (particularly for machines please indicate your telephone number, too) and possibly the offer number from Ebay. As an existing customer please tell us your customer number, so that BZT can collect fast all information necessary for an offer. You can reach our sales team by This e-mail address is being protected from spambots. You need JavaScript enabled to view it better we can agree with you with a possible telephone call, the better will be our advice.

In case of doubt please speak with our sales department by dialling 0049 5202 9930686.

Which components belong to the scope of delivery?

Please have a closer look at the section “Scope of delivery”. If you need something different, please get in contact with our sales team by dialling 0049 5202 9930686.