<p><em>Rancang bangun mesin amplas sistem sabuk bertujuan untuk melengkapi peralatan uji kekerasan dan metalografi pada laboratorium Teknik Mesin Politeknik Negeri Semarang. Sampai saat ini pengerjakan permukaan benda kerja masih menggunakan mesin gerinda yang ada pada bengkel mesin, sehingga memakan waktu untuk menyelesaikan pengujian baik metalografi maupun kekerasan pada laboratorium pengujian bahan.Pembuatan mesin amplas sistem sabuk dilakukan memodifikasi cara kerja mesin gerinda yang lazim menjadi sistem sabuk berputar. Metode pembuatan mesin dimulai dari mendesain, pembuatan komponen, perakitan, pengujian mesin dan analisa hasil pengujian. Mesin amplas system sabuk yang dihasilkan dengan penggerak motor listrik 0,5 HP, putaran 1400 rpm. Sistem transmisi pemutar sabuk menggunakan reducer 1 : 40 dan sabuk puli. Jenis amplas yang digunakan merk Deerfos 80 Hv. Hasil pengujian pengamplasan dengan mesin ini mencapai kekasaran permukaan N8 sama dengan hasil pengamplasan menggunakan mesin gerinda yang ada pada bengkel mesin. Kapasitas pengamplasan yang dicapai sama dengan kapasitas mesin gerinda sebesar 0,271 mm³/detik<strong>.</strong></em></p><strong></strong><em></em>

The squeezing process of grated coconut into coconut milk, and the following process of making the milk into coconut oil, which is done by people living in rural areas, is until now still very traditional. They do it manually (by hands) so that they produce 7.2 kg/hour grated coconut or 3.6 litres/hour thick coconut milk.To effectify the process, the squeezing needs to be mechanized, using a grated coconut squeezer machine.The machine is designed on the basis of Screw Press system with a ¼ HP 1450 rpm electric motor power using a pulley belt transmission and a gear box. The squeezer's force refers to coconuts aging between 341 and 413 days (hand squeezing force normally practised by coconut oil producers in rural areas).This prototype of machine has the capacity of producing 53.2 kg/hour grated coconut or 26.6 litres/hour thick coconut milk, which has similar quality (in colour, smell and texture) as that manually squeezed.

<p><em>Mesin penanam bibit padi manual dengan penggerak tenaga manusia melalui transmisi engkol, dipandang masih belum menghasilkan fungsi yang diharapkan. Modifikasi dilakukan guna efisensi dan ekonomis, dengan pemberian penggerak motor bensin 1,8 HP dan setting link garpu serta pengaturan putaran motor, menghasilkan penanaman padi sesuai spesifikasi menanam padi pada jarak tanam 250 mm. Mesin hasil modifikasi ini berkapaistas 60 tancap setiap menit pada luas lahan 8 m²</em><em>.</em></p>

Domestic market of shoes is increasing. Howewer this opportunity is yet to be grasped by domestic producers. Lack of quality is of identified obstacles of the domestic products which are mostly produced by household industries to compete in the market. An aspect of the quality is product's appearance that is influenced by quality of raw material which is leather. Hence, this recent research aims to design machine that can be used to yield better quality leather. In each 8 hours the machine can produce ready-to-used leather for 100 pairs of shoes.

The paper reports an experiment to produce polyvinyl chloride (PVC) using local (from Gunung Kidul) and imported (from Taiwan) CaCO3. The laboratory test shows that PVC produced using Taiwanese CaCO3 is superior over that using local CaCO3 in terms of its flexibity. Hence, it is not recommended to use local CaCO3 producing PVC-based products that requires high flexibility such as water pipe, cable isolator. On the other hand, the local PVC may be used to produce, for instance, blinds and compressor.