Plastic injection moulding for speaker grilles in cars
Company profile
Firm:
Troquelería Ura
Address: Zamudio, Bizkaia,
Spain.
Business: manufacture of moulds for the injection
of plastic, rubber, and aluminium, aimed at car makers, telecommunications
firms, electronics firms, etc.
Markets: Spain, Germany, France, Holland, Switzerland,
United Kingdom.
Year set up: 1971.
Number of employees: 38.
Penetration EDM equipment: TECHNO H-700, TECHNO
H-400 (two units), PV 4.6 EO, D-2030, PV 4.60 EO.
Person to contact: Manolo García.
Work characteristics
| Machine: | TECHNO H-400 with Expert system. | Radial roughing gap: | 0.150 mm (0,0059 in). |
| Electrode: | Graphite POCO EDM3. | Number of electrode orifices: | 22,000. |
| Area on front part of electrode: | 550 cm²(85,25 in2). | Orifice diameter: | 0.9 mm (0,035 in). |
| Workpiece: | Steel. | Final surface-finish: | 20 VDI. |
Ura Troquelería is a leading firm in the manufacture of high-precision, highly-complex injection moulds.
Manolo García, a founding partner, recognizes that to be competitive in such a demanding market it is necessary to invest constantly.
"This year we plan an outlay of 900,000 euros" says Mr García. "Recently we acquired two new penetration EDM machines, a TECHNO H-400 and another TECHNO H-700, each with an Expert Erosion System. Only if we have the most advanced technological equipment can we take on the steadily more difficult jobs that are there to be done. The tough lead times that our clients impose oblige us to work not only precisely but also quickly."
The new TECHNO H-400 was installed six months ago, and in Mr García's opinion its advantages are considerable. "The Expert Erosion System means that with a lot of jobs we can halve the amount of time required," he says. "And also there's much less electrode wear. Now we accept jobs we used to fear we would be unable to do."
Take for example one of the moulds that the company has just manufactured. It's a plastic-injection mould for a prototype loudspeaker grille for SEAT, the car makers. A job of this sort is truly a challenge, especially since the grille in question has a front area of 550 cm² (85,25 in2) and as many as 22,000 holes. These are 1.75 mm (0,069 in) apart, with a diameter in each case of 0.9 mm (0,035 in). So that subsequently the workpiece injected can be quickly taken out of its mould, it is essential also that the final surface finish be well done.
One of the factors that made the construction of this mould even more difficult was the fact that the gap available was only 0.150 mm (0,0059 in), for which reason orbital erosion was very constrained. Good surface finish was thus problematic. Only with state-of-the-art EDM equipment can one perform such a demanding job. With the Expert System that is part of the new TECHNO machines, it can be done. And with a 20 VDI surface finish.
The speaker grille has a front area of 550 cm² (85,25 in2) and as many as 22,000 holes, each with a diameter of 0.9 mm (0,035 in)
