Improved Viscosity Prediction on MIM Feedstocks

At Euro PM 2015, organized by the European Powder Metallurgy Association (EPMA) in Reims, France, between October 4th and 5th, Sigmasoft Virtual Molding Chief Technical Officer Timo Gebauer will give a presentation describing how the correct viscosity can be calculated for MIM (Metal Injection Molding) feedstocks.

Sigmasoft Virtual Molding can accurately predict the flow behavior in MIM, accounting for viscosity variations induced by shear heating and particle segregation.
Sigmasoft Virtual Molding can accurately predict the flow behavior in MIM,
accounting for viscosity variations induced by shear heating and particle segregation.

Sigmasoft Virtual Molding is able to predict shear heating and particle segregation, and to couple these effects to predict the real feedstock viscosity. This accurate modelling delivers a better description of the flow behavior and a far more precise pressure demand prediction, a key parameter to determine proper machine size and processing profitability.

Sigmasoft Virtual Molding is already a well-established tool in MIM processes, to predict feedstock molding behavior and its thermal interaction with the mold. To simulate the feedstock flow behavior inside the cavity, viscosity is a key parameter. However, the methods used to characterize viscosity in thermoplastic materials may not be suitable for the characterization of MIM feedstocks.

There is no testing device available to directly measure the viscosity; the values are always calculated indirectly. The most common way to determine the viscosity of polymers at high shear rates is the high pressure capillary rheometer (HCR). The measurements are corrected with theoretical models, but the temperature increase produced by heat dissipation is assumed to be low enough to be neglected. This assumption is accurate enough for thermoplastic materials at low shear rates. However, as the shear rate increases, the heat dissipation due to molecular friction (a phenomenon known as shear heating) starts to be important.

In MIM feedstocks, besides the high shear heating, the rheological behavior can be even more complex, because the shear field leads to particle segregation . Since
viscosity is a function of the powder concentration in MIM feedstocks, this segregation leads to significant differences in local viscosity and thus in local flow deformation. “One way to get the right viscosity for a MIM feedstock is to measure it with different particle concentrations. Once the viscosity based on the concentration is known, it is possible to use Sigmasoft Virtual Molding to calculate the correct viscosity”, states Gebauer.

Renishaw unveils Inspection Plus with SupaTouch™ optimisation delivering intelligent speed

Intelligent software optimises on-machine probing cycles. Renishaw, a market-leading engineering technologies company, will introduce Inspection Plus with SupaTouch™ at EMO 2015, Milan, Italy (5th-10th October). This enhanced software package automatically optimises on-machine measurement cycles to minimise cycle time and maximise productivity.

probe and clock

The software features an easy-to-use optimisation process to automatically determine and select the highest feedrates a machine tool can achieve whilst maintaining measurement accuracy. It also uses intelligent in-cycle decision making to implement either a one or two-touch probing strategy for each measurement routine.

Inspection Plus with SupaTouch optimisation eliminates the need for manual optimisation of on-machine positioning feedrates, measurement feedrates and strategies. When compared with traditional software cycles, it provides a significant cycle time reduction of up to 60% on CNC machine tools.

To ensure maximum accuracy, the software detects any measurements taken during machine acceleration or deceleration phases and compensates for errors by taking corrective action and remeasuring. It also introduces a calibration process that improves measurement repeatability in all directions and improves the accuracy of probe positioning during multi-axis vector moves.

Inspection Plus with SupaTouch optimisation enhances the many proven benefits of Renishaw’s established Inspection Plus software. With this new software, users can significantly improve cycle times and on-machine measurement results, maximising the productivity and profitability of their machine tools.

Delcam’s new PowerMILL CAM can mirror complete machining projects

Delcam has launched the 2016 version of its PowerMILL programming software for five-axis and high-speed machining.

In PowerMILL 2016, time can be saved by mirroring programs for symmetrical parts or tooling
In PowerMILL 2016, time can be saved by mirroring programs for symmetrical parts or tooling

The main enhancement in the new release is the ability to mirror complete machining projects in one operation and to maintain automatically the machining characteristics, for example to choose automatically whether climb or conventional milling should be used in each section of the toolpath. Previously, only individual toolpaths could be mirrored.

Automatic mirroring saves considerable time whenever right- and left-hand versions are needed of a part or tool. It will also be faster to program the machining of symmetrical objects since it will be possible to program one half and then mirror the toolpaths to complete the program.

To ensure that the mirroring has performed as expected, the new option can be used with the ability, introduced in PowerMILL 2015 R2, to undertake complete verification of a project for machine-tool issues such as collisions. Comprehensive verification can be performed, including ensuring that the machine tool is capable of running the mirrored toolpaths, as well as checking for both machine-tool collisions and tooling collisions.

PowerMILL 2015 R2 also saw the introduction of the ability to simulate machine-tool movements as tool changes are executed. The capability has been enhanced in the 2016 release by allowing more complex tool changes to be simulated, in particular those involving a carousel mechanism.

Other improvements to simulation in PowerMILL 2016 include a new form to print out the position of the cutting-tool tip during simulation, an auto-translucency option that will allow viewing of the table attach point at all times, and the ability to draw translucently the safe areas for rapid moves.

Development work has continued on the optional modules for PowerMILL as well as to the main program. In particular, a new, more efficient strategy to machine single blades has been developed for the Blades, Blisks & Impellors module, and a constant-Z machining option has been added to the module for programming the machining of ribs into tooling.

Survey results confirm MEX success

Strong début in Stuttgart: Moulding Expo performs above average in the official survey results. 78% of the exhibitors surveyed rate the event as “very good/good”, 90% would recommend MEX and 83% consider the quality of professional visitors as “very good/good”. “These are superb figures, which are also being currently confirmed in our conversations with the exhibitors”, states Florian Niethammer, Senior Project Manager of Moulding Expo. “Over 100 exhibitors have already booked their stand for 2017. As an event organiser, we are delighted that our organisation, date and frequency, as well as the location of Stuttgart, received great praise and thus contributed to the success of the event.” Moreover, 74% of the exhibitors are certain that MEX will establish itself as a permanent fixture and continue to grow.

Metal production process for dental crown
Metal production process for dental crown

Visitors: Industry needs this new trade fair
The satisfaction of the exhibitors is also reflected in the visitor survey. 70% want to come back again and 83% would recommend the trade fair. “The feedback that the market needs a new trade fair with the right exhibitors caught our attention”, states Niethammer. “An important unique selling point of our event is the high number of tool, pattern and mould makers at 39%. A concept which has proved a success and which we will continue to pursue.”

In total, around 14,000 visitors (excluding synergy visitors from Control) travelled from 52 countries to Stuttgart to be at the première. 31% of visitors travelled over 100 kilometres to Moulding Expo and 21% over 300 kilometres. “As a result, MEX managed to be certified as an international trade fair right from the get-go. The certification according to FKM, the Society for Voluntary Control of Fair and Exhibition Figures, is an important seal of approval”, according to the project manager. 75% of visitors came from industry and 36% from the middle, higher or top management level of companies. A third of the visitors came from smaller companies (up to 50 employees), a third from medium-sized companies (up to 500 employees) and a third from large companies (1,000 and more employees) – a very homogeneous composition.

“For us, it was also important that at our trade fair the industrial buyers and the suppliers of tool, pattern and mould making exchanged information and ideas directly”, states Florian Niethammer. “We succeeded with the forum of the German Association of Materials Management, Purchasing and Logistics.” The participants of the BME Forum, including several decision-makers from important large companies, were brought together with the exhibitors of Moulding Expo during guided tours of the trade fair. Niethammer also rated the concept for the presentation of apprenticeship and in-service training in tool, pattern and mould making as a success. Under the title “MEX: Training 4.0”, the associations and companies in Hall 4 provided an interactive presentation of the wide range of apprenticeship and training options in the industry.

But the first Moulding Expo managed to not only entertain the young talent – it also provided a stage for a pioneer of tool construction and mould making: Karl-Heinz Möller. In a ceremony during the exhibitor evening the industry awarded the 93-year-old publisher with a lifetime achievement award.

MEX 2017: Preparations in full swing
According to Florian Niethammer, Moulding Expo still has development potential in its international alignment. In 2015, 25% of the exhibitors came from abroad, mainly from the neighbouring countries in Europe. This focus is to be retained. “We don’t want unreasonable growth, but we specifically want to open more markets together with our partners”, states the MEX Project Manager. Every new exhibitor must fit into the concept of the trade fair. “The quality of the products and services on offer thus remains the decisive criterion.”

The next Moulding Expo will take place in May 2017. The exact date will be announced in autumn 2015.