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Here you will find several of our reference customers plus examples, which prove how the users have experienced the usefulness of PROMETEC Monitoring and Optimization Systems:

  • Overview
  • Milling of sleeves
  • Turning (cast and rough parts)
  • Turning (Aluminum)
  • Profilating
  • HPC milling cutters
  • Rotary transfer machine
  • Spiral bevel gears
Breakage detection at milling of sleeves
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Tested at Getrag Ford Transmissions GmbH, Cologne, Germany
Machine Präwema GmbH Synchro Form V (image: Präwema)
Päwema Synchro Form V
Workpiece Sliding sleeve
Schiebemuffe
Material steel (Image: Sliding sleeve and multi-purpose tool, source: Präwema)

Monitoring taskIn manufacturing of transmissions the sliding sleeves run through a lot of procedures until final completion. For example the gear cutting of the sleeve is subject to a slight milling (groove) done by means of a two-edged milling tool.

In the past it happened that one cutting edge of the tool broke off resulting in an incorrect performance of the milling process and consequently in production of scrap.
A later manual visual checking of the rejects is not possible owing to the slightness
of the feature and includes further uncertainties.
The customer wants a system which is monitoring the process parallel to primary processing time and stopping the machine in case of tool breakage or in case of a damage in cutting (chipping) to prevent further production of rejects.

Hinterlegngsfräsen Systemaufbau

Conclusion It was confirmed that the applied measuring technique is perfectly suited for a continuous monitoring of milling on the manufacture of sleeves. The measuring signals are representing the process clearly and interpretably and have a very good accuracy of repeats.
In case of tool breakage a clear modification/reduction of the measuring signal occurs so that different tool monitoring strategies can be applied.

While plunging the grooves, which is done by using the same multi-purpose tool, an increased wear of the cutting edge arose that was detected and monitored reliably by means of vibration measuring technique.
The desired process safety and a 100% check of the workpieces can be realized by application of the PROMOS 2 system on the Präwema machines.

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Dynamic Limits
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Dynamic Limits

Tool breakage detection in turning of cast and forged parts (initial cut)

Eisenbahnrad drehen

PROMETEC's Dynamic Limits are the best solution for tool breakage detection in turning of cast and forged parts.

The part to be machined - e.g. a brake disk, a flywheel, a sprocket blank or a train wheel - is out-of-roundness, has an undulating material surface with pronounced hardness fluctuations in its outer surface and can only be clamped off-center. So the force signal detected by the sensor shows strong fluctuations:

1. Pronounced signal fluctuations

The animation displays pronounced fluctuations in the force signal:

Where should the feed stop limit be placed? (see the following segment)

2. Static Limit: faulty breakage detection

If a Static Limit for breakage detection is placed at for e.g. 160%, this could cause false alarms and unwanted switch-off of the workpiece feed due to the natural signal fluctuations:

Where should the limit be placed now? Higher? This would render the breakage detection unusable. Lower? This would create even more false alarms. The perfect solution in this case are:

3. Dynamic Limits

The Dynamic Limits (in combination with fast force sensors) are continuously adjusting to the measured signal and therefore tolerate dynamic signal changes. Adjustment of the Dynamic Limits takes place within cycles of milliseconds and thus several times within a single workpiece rotation.

The unexpected extreme signal peak (for example a harder area in the material or an extreme material allowance, see arrow) is tolerated and no false alarms are generated. The machining process is not interrupted!

4. Dynamic Limit in case of breakage

What will happen when an actual breakage occurs? A sudden signal change, typical for breakage, changes the behavior of the Dynamic Limits - they are are violated and „freeze“ immediately - right where they were:

A fast analysis for atypical breakage signal profile occurs: only if an actual tool breakage happened, the workpiece feed of the machine is stopped, a different analysis (like hard spots, cut interruption etc.) will not stop the machining!

Conclusion:

Dynamic Limits need minor operating expense only, more than 95% of the breakage events in turning of cast or forged parts are detected. Extremely few false alarms (typical: 1 per shift/week) are generated.
The very short reaction time of 5 milliseconds enables a feed hold within a single revolution of the workpiece after a breakage occurred, which protects the tool holder.

Example


Turning of pistons
(back to overview)

Breakage Monitoring in Lathes, Piston manufacturing (Aluminum)
Manufacturer KS Kolbenschmidt GmbH, Neckarsulm, Manufacturing of car and truck pistons
Lathe Weisser Vertor C-1R
Weisser Vertor
Control Sinumerik 840 D

Machining Car and truck pistons
LKW Kolbenfertigung
Material Aluminum alloy

Machining - Monitoring Task Especially turning the bottom hole may cause a chipping jam, leading to tool breakage. The pure software solution PROSIN is used for tool breakage monitoring and as a protection against static overload.

Monitoring Function The monitored drive current signal exceeds an overload limit in case of the jam mentioned before – PROSIN switches off the machine in time and activates a warning light via NC digital output. The user is able to react immediately and thus reducing the idle times to a minimum. Furthermore machine and tool holder are damage-protected by PROSIN.

Amortization Because of the replaceable cutting insert’s low cost a detroyed tool is not much of a problem here. But the chances are that any tool breakage not detected in time will lead to a secondary damage of tool holder and turret head. The resulting repair costs and the loss of production make for an Amortization of PROSIN at the first tool breakage!

Bedienerakzeptanz According to the users at Kolbenschmidt PROSIN permits an effective value, because the software solution can be used to full extend due to its plausible concept and its simple operation. Especially today’s multi machine operation makes a powerful and easy-to-use (almost self-explaining) tool monitoring solution a must-have, to ensure a secure and economic production.

Source: KS Kolbenschmidt GmbH, Neckarsulm

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Profilating, Polygon turning unit for castle teeth machining
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Breakage detection at Profilating

User data Wera Profilator, Wuppertal
Wera Profilator

Process/Problem Manufacturing of the annulus gears of automatic gearboxes.
Hohlrad Wera

Tool Polygon turning unit for castle teeth machining. One cutter head with five cutting edges and five internal broaching tools is used for this manufacturing process.
Hohlradbearbeitung

Even little damages on the single tools can produce bad processing results, insufficient component quality or a later failure of the installed component.
As the cutting cross sections are very small for the processing of the castle teeth, the process and tool monitoring is only possible by means of a more than high-resolution monitoring technique.

Specialities of installation Here a vibration sensor and the algorithm Peak Analyser I² are used, allowing for a safe and complete monitoring of breakages on the cutting inserts of the cutter head.

Peak Analyzer I2

  • Breakage detection of a single tool edge
  • Prevention of follow-up breakages
  • No production of scrap
  • No damage of tool holder

Conclusion Commissioning of the PROMOS-2-System on Profilator machines lead to process safety as desired and enabled a 100% in-process detection of tool breakage.

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HPC Milling Cutters
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Wear Monitoring of HPC milling cutters, valve manufacturing
User Bürkert, Ingelfingen
Werkzeug Bürkert
Machine Data Stama MC, 2 spindles
Control type SIEMENS, PCU50
Work piece Valve, Material: V4A
Monitoring task The installation wanted to prove that a wear monitoring could be implemented
with the pure software solution PROSINPLUS (work value monitoring) – which would
1. lower the tool cost and
2. prevent combustion of the coolant and lubrication fluid, which occasionally happens because of damaged and then smouldering cutting inserts or swarfs.

defekte Schneidplatten

Monitoring solutionIn collaboration with Bürkert company (in charge of the project: Mr Hlawatschke)
a tool life experiment on a HPC milling cutter (size 25/3) with 4 cutting edges was conducted. Teach-In was executed with two tools in mint condition. The taught value was 5.78 A for both spindles (work value spindle 1: 39773 work value spindle 2: 41287). After machining of another work piece, a worn tool without any breakout was placed on spindle 2. The monitoring limits were finally set to an overload limit of 130% and a work limit of 120%. According to the tool setter this was still okay. The results of the following cuts are shown in this table:

HPC Tabelle

The final cut triggered the overload limit of spindle 2 at the start of the cut and stopped the machine instantly, resulting in a low work value of both spindles.
The photo (tool on spindle 2) illustrates the condition of the tool. According to the tool setter this was the exact moment to switch off the machine for a tool change to avoid smoldering of the cutting inserts or to avoid swarfs. First breakouts are visible on the inserts.

Conclusion Wear monitoring was possible on this tool. The development of the monitored values corresponds with the tools’ condition. A large variation of the values, because of the work piece fluctuations or material variations is unlikely, as the cutting conditions are very stable.
For an exact setting of the monitoring limits (considerably low) know-how of the operator/tool setter is important. Like shown above, the exact values can be determined by tool life tests. We still recommend an evaluation by using the Work Value monitoring strategy, which is integrated as a default into PROSINPLUS.

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Rotary Transfer Machine (oil pan/tooth belt tensioner)
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Breakage Monitoring in Rotary Transfer Machine
User Stöferle, Laupheim, Germany
Werkzeugmaschine Stöferle Rotary Transfer machine RTZ-NC-22-500 (planet diameter 500, 22 NC-Achsen)
Stoeferle
Control SINUMERIK PCU 50

Machining of the oil pan The pure software solution PROSIN is used for drill breakage monitoring for protection of the successional tool as well as for monitoring the milling processes as an overload protection.
The workpiece is machined at 4 of 6 stations of the rotary cycle center. For the drill of station 2 (∅ 41 mm) PROSIN additionally is used for wear monitoring. The tool drills into the solid material, its wear is subject to considerable fluctuations and monitoring cannot be sufficiently done by a simple tool life checking.
Prosin enables the Detection of “out-of-specification” parts, which may happen by incorrect clamping of the oil pan (three-point-clamping). As a result, the workpiece will protrude too far to the front, resulting in machining too much material off the seating of the anti-splash sheet: The workpiece will not conform to specifications. PROSIN detects and rejects the part by utilizing the overload limit.

Ölwanne

Station 1:
Loading/Testing
Station 3:
• Form tap M10
• Milling cutter ∅ 32mm
• Drill ∅ 41mm

Station 5:
• Form tap M6
• Core drill 5.5mm

Station 2:
• Milling cutter PCD tool ∅ 80mm
• Core drill ∅ 9.3mm
Station 4:
• Core drill ∅ 5.5mm
• Angled drill ∅ 12.5mm
(Combined tool for counter sinking of sealing surface)
• Die tool M14x1.5 (oil drain plug)
Station 6:
Unloading/Testing/Measuring

Machining of the tooth belt tensioner Regarding drill breakage monitoring and overload protection the same applies as for the oil pan.

Trägerriemenspanner
Here, too, PROSIN detects out of specification parts: In the rare occasion that a blank part is warped, a Missing-Limit detects the low machining load. As a consequence the part will be sorted out..

Advantage user acceptance According to the users at Stoeferle PROSIN permits an effective value, because the software solution can be used to full extent due to its plausible concept and its simple operation.

ConclusionIn today’s multi machine operation PROSIN makes for a powerful and easy-to-use (almost self-explaining) tool monitoring solution to ensure a secure and economic
production.

Stöferle CNC-RTZ-320:
4 independent CNC units
6 Planet tables independently rotatable in 1 degree steps
24 respectively 32 tool seats
- HSK 63 adapter
- Custom tool heads possible for tapping etc.

Station 1:
• PCD Milling cutter ∅ 24mm
• PCD Milling cutter ∅ 22 mm
Station 3:
• Core drill ∅ 7.37mm
• Drill ∅ 8.1mm
Station 2:
• PCD Drill ∅ 15.95 mm
• 90° Counter sinking tool
• Side milling cutter ∅ 100mm
Station 4:
• Multispindle drill head 4x thread M8 with one drive
• M8 Form tap
• Drill ∅ 5.6 mm

 

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Machining of spiral bevel gears
(back to overview)

Tool wear detection at machining of spiral bevel gears
according to the Gleason and Oerlikon method
User German automotive manufacturer

Machine Gear hobbing mill for spiral bevel gears

Workpiece spiral bevel gears, steel
(pic.: ring gear and bevel gear)
Spiralkegelrad

Tool
(pic.: Inserted tooth milling cutter)
Stirnmesserkopf

MachiningThis application should prove the applicability of the PROMETEC Real Time Compact Monitor (RTCM) with vibration sensor VBS 50 for monitoring of hobbing processes.
Primarily the system must detect wear on the inserted tooth milling cutter as early as possible and it must be able to detect the end of life of the tool.
Early announcement of the tool's end of life should avoid tool overload and thus the danger of a total breakage and scoring or drag marking of the tooth flanks will be avoided.

System configuration
Systemaufbau Wälzfräsen

Results The following image displays the I2 Mean values of 381 machinings.
Wälzfräsen
The I2 value shows a significant wear trend as well as an increased build-up because of lower workpiece quality. Thus, wear monitoring with defined limits is possible.

Conclusion The PROMETEC PROMOS 2(RTCM) System provides the ideal possibility to safely detect the end of life of gear hobbing mills. Thus, several interesting and quantifiable economical advantages arise.
Continuous recording of the process values makes it possible to display wear trends and the tool can be protected against wear-induced overload. The integrated "end of life" message prompts the operators to inspect the tool for any wear marks. Excessive score or drag marking on the surface of the teeth (or on their base) can be avoided by continuous checking of the wear status of the tool. This should lead to a considerable reduction of rework and lower costs.

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